正則入門連載！（獻給不及格的程序員們）第3/4頁

更新時間：2007年02月05日 00:00:00 作者：

優(yōu)先級順序
說明如何計算正則表達式以及正則表達式的序列和語法對結果有何影響。

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> <HTML xmlns:MSHelp="http://msdn.microsoft.com/mshelp" DIR="LTR"> <style type="text/css"> /* VERSION 9345 Designed for IE5.x. Optimal in IE 6.x CSS for use with Developer Tools Documentation Localizable definitions: font families font sizes */ /* --------------------------------------------------                   MAIN TOPIC STYLES -------------------------------------------------- */ div.saveHistory     {     behavior:url(#default#savehistory);     text-decoration: underline     } body /* This body tag requires the use of one of the sets of banner and/or text div ids */     {     margin: 0px 0px 0px 0px;     padding: 0px 0px 0px 0px;     background: #ffffff;      color: #000000;     font-family: 瀹嬩綋, Verdana, Arial, Helvetica, sans-serif;     font-size: 75%;     width: 100%;     } div#scrollyes /* Allows topic to scroll with correct margins. Cannot be used with running head banner */     {     /* Must immediately follow <body>. */     padding: 2px 15px 2px 22px;     width: 100%;     } div#nsbanner /* Creates Nonscrolling banner region */     {     position: relative;     left: 0px;     padding: 0px 0px 0px 0px;     border-bottom: 1px solid #999999;     } div#nstext /* Creates the scrolling text area for Nonscrolling region topic */     {     padding: 5px 10px 0px 22px;      } div#scrbanner /* Creates the running head bar in a full-scroll topic */     {     /* Allows topic to scroll. */     margin: 0px 0px 0px 0px;     padding: 0px 0px 0px 0px;     border-bottom: 1px solid #999999;     } div#scrtext /* Creates the text area in a full-scroll topic */     {   /* Allows topic to scroll. */ /*    width: 100%; /* Forces tables to have correct right margin */*/     padding: 0px 10px 0px 22px;      } div#bannerrow1 /* provides full-width color to top row in running head (requires script) */     {     background-color: #99ccff;     } div#titlerow /* provides non-scroll topic title area (requires script) */     {     width: 100%; /* Forces tables to have correct right margin */     padding: 0px 10px 0px 22px;      background-color: #99ccff;             } /* --------------------------------------------------                     HEADING STYLES -------------------------------------------------- */ h1, h2, h3, h4     {     font-family: 瀹嬩綋, Verdana, Arial, Helvetica, sans-serif;     margin-bottom: .4em;      margin-top: 1em;     font-weight: bold;     } h1     {     font-size: 120%;     margin-top: 0em;     } div#scrollyes h1 /* Changes font size for full-scrolling topic */     {     font-size: 150%;     } h2     {     font-size: 120%;     } h3     {     font-size: 115%;     } h4     {     font-size: 100%;     } .dtH1, .dtH2, .dtH3, .dtH4     {     margin-left: -18px;     } div#titlerow h1     {     margin-bottom: .2em     } /* --------------------------------------------------                      TEXT STYLES -------------------------------------------------- */ p     {     margin: .5em 0em .5em 0em;     } blockquote.dtBlock     {     margin: .5em 1.5em .5em 1.5em;     } div#dtHoverText     {     color: #000066;     } .normal     {     margin: .5em 0em .5em 0em;     } .fineprint     {     font-size: 110%; /* 90% of 70% */     } .indent     {     margin: .5em 1.5em .5em 1.5em;     } .topicstatus /* Topic Status Boilerplate class */     {     display: block;     color: red;     } /* --------------------------------------------------                      LABEL STYLES -------------------------------------------------- */ p.label     {     margin-top: 1em;     } p.labelproc     {     margin-top: 1em;     color: #000066;     } /* --------------------------------------------------                     GRAPHIC STYLES -------------------------------------------------- */ img     {     border: none;      } /* --------------------------------------------------                      LIST STYLES -------------------------------------------------- */ ol, ul     {     margin: .5em 0em 0em 2em;      } li     {     margin-bottom: .5em;     } ul p, ol p, dl p     {     margin-left: 0em;     } ul p.label, ol p.label     {     margin-top: .5em;     } /* --------------------------------------------------                DEFINITION LIST STYLES -------------------------------------------------- */ dl     {     margin-top: 0em;      padding-left: 1px; /* Prevents italic-letter descenders from being cut off */     } dd     {     margin-bottom: 0em;       margin-left: 1.5em;      } dt     {     margin-top: .5em;      } /* --------------------------------------------------            CODE, SYNTAX, and REFTIP STYLES -------------------------------------------------- */ pre     {     margin-top: .5em;     margin-bottom: .5em;      } pre, code, .code     {     font: 100% 瀹嬩綋, Courier New, Monospace, Courier;/* This is 100% of 70% */     color: #000066;     } pre b, code b     {     letter-spacing: .1em; /* opens kerning on bold in Syntax/Code */     } pre.syntax     {     font: 100% Courier New, 瀹嬩綋, Monospace, Courier;/* This is 100% of 70% */     background: #cccccc;     padding: 4px 8px;     cursor: text;     margin-top: 1em;     margin-bottom: 1em;      color: #000000;     border-width: 1px;     border-style: solid;     border-color: #999999;     } /* --------------------------------------------------                       LINK STYLES -------------------------------------------------- */ a:link     {     color: #0000ff;     } a:visited     {     color: #0000ff;     } a:hover     {     color: #3366ff;     } /* --------------------------- MSHelp\:link - Help HxLinks --------------------------- */ MSHelp\:link     {     text-decoration: underline;      color: #0000ff;      hoverColor: #3366ff;     filterString: ;     }     A.HxLinkTable /* MSHelp\:link - Table disambiguation elements */     {     } /* --------------------------- MSHelp\:ktable - Help links --------------------------- */ MSHelp\:ktable     {     disambiguator: span;     separator: &nbsp|&#32;     prefix: |&#32;     postfix: &nbsp;     filterString: ;     } div.HxLinkTable     {     width: auto; /* Forces tables to have correct right margins and top spacing */     margin-top: -.4em;     visibility: visible;     } ol div.HxLinkTable, ul div.HxLinkTable     {     margin-top: 0em; /* Forces tables to have correct right margins and top spacing */     } table.HxLinkTable /* Keep in sync with general table settings below */     {     width: auto;     margin-top: 1.5em;     margin-bottom: .3em;     margin-left: -1em;     border-width: 1px 1px 0px 0px;     border-style: solid;     border-color: #999999;     background-color: #999999;      font-size: 100%; /* Text in Table is same size as text outside table */     behavior:url(hxlinktable.htc); /* Attach the behavior to link elements. */     } table.HxLinkTable th, table.HxLinkTable td /* Keep in sync with general table settings below */     {      border-style: solid; /* Creates the cell border and color */     border-width: 0px 0px 1px 1px;     border-style: solid;     border-color: #999999;     padding: 4px 6px;     text-align: left;     } table.HxLinkTable th /* Keep in sync with general table settings below */     {      background: #cccccc; /* Creates the shaded table header row */     vertical-align: bottom;     } table.HxLinkTable td /* Keep in sync with general table settings below */     {     background: #ffffff;     vertical-align: top;     } /* --------------------------------------------------                     TABLE STYLES -------------------------------------------------- */ div.tablediv     {     width: 100%; /* Forces tables to have correct right margins and top spacing */     margin-top: -.4em;     } ol div.tablediv, ul div.tablediv, ol div.HxLinkTable, ul div.HxLinkTable     {     margin-top: 0em; /* Forces tables to have correct right margins and top spacing */     } table.dtTABLE     {     width: 100%; /* Forces tables to have correct right margin */     margin-top: .6em;     margin-bottom: .3em;     border-width: 1px 1px 0px 0px;     border-style: solid;     border-color: #999999;     background-color: #999999;      font-size: 100%; /* Text in Table is same size as text outside table */     } table.dtTABLE th, table.dtTABLE td     {      border-style: solid; /* Creates the cell border and color */     border-width: 0px 0px 1px 1px;     border-style: solid;     border-color: #999999;     padding: 4px 6px;     text-align: left;     } table.dtTABLE th         {      background: #cccccc; /* Creates the shaded table header row */     vertical-align: bottom;     } table.dtTABLE td         {     background: #ffffff;     vertical-align: top;     } /* -------------------------------------------------- ISSUE REPORTING AND MISC LINKS TOPIC FOOTER -------------------------------------------------- */ div.footer     {          } div.footer hr     {     color: #999999;     height: 1px;     } /* --------------------------------------------------              STYLES FOR RUNNING HEADS -------------------------------------------------- */ table.bannerparthead, table.bannertitle /* General values for the Running Head tables */     {     position: relative;     left: 0px;     top: 0px;     padding: 0px 0px 0px 0px;     margin: 0px 0px 0px 0px;     width: 100%;     height: 21px;      border-collapse: collapse;     border-style: solid;     border-width: 0px;     background-color: #99ccff;      font-size: 100%;     } table.bannerparthead td /* General Values for cells in the top row of running head */     {     margin: 0px 0px 0px 0px;     padding: 2px 0px 0px 4px;     vertical-align: middle;     /*border-width: 0px 0px 1px 0px; */     border-width: 0px     border-style: solid;     border-color: #999999;     background: transparent;      /* font-style: normal; */     font-weight: normal;     } table.bannerparthead td.product /* Values for top right cell in running head */     {                       /* Allows for a second text block in the running head */     text-align: right;     padding: 2px 5px 0px 5px;     } table.bannertitle td /* General Values for cells in the bottom row of running head */     {     margin: 0px 0px 0px 0px;     padding: 0px 0px 0px 3px;     vertical-align: middle;     border-width: 0px 0px 1px 0px;     border-style: solid;     border-color: #999999;     background: transparent;     font-weight: bold;     } td.button1 /* Values for button cells */     {     width: 14px;     cursor: hand;     } /* =================================================             STYLES REQUIRED BY THE SCRIPT */ /* --------------------------------------------------                   SAMPLE VIEWER -------------------------------------------------- */ div#smpMgrCell     {     display:none;     } table.SampMgr     {     margin: 0px 0px 0px -22px;     } table.SampMgr td     {     padding-left: 22px;     } /* -------------------------------------------------- RUNNING HEAD BAR POPUP STYLES: See Also, Requirements, MultiLang Filtering -------------------------------------------------- */ div.sapop, div.langMenu /* See Also & Requirements popups */     {     position: absolute;     left: 0px;     z-index: 1;     width: 50%;     padding: 0px 8px 5px 26px;     visibility: hidden;     border: 1px solid #999999; /* Same as all other border colors */     background: #ffffcc;     } div.langMenu /* MultiLang Filter popup */     {     padding: 10px 10px 10px 10px;     } div.langMenu ul     {     list-style-type: none;     padding-left: 5px;     margin-left: 0px;     } .lang, .ilang /* controls the multilang tag styles */     {     color: #333333;     font-family: Verdana, Arial, 瀹嬩綋, Helvetica, sans-serif;     font-size: 80%;     font-weight: normal;     font-style: normal;     } h1 .lang, h1 .ilang      {     font-size: 80%;     } div.filtered     {     margin-top: .6em;     margin-bottom: .6em;     margin-left: -7px;     padding: 0px 0px 0px 6px;     border-left: 1px solid #999999;     background: #ffffff;     } div.filtered h1, div.filtered h2, div.filtered h3, div.filtered h4     {     margin-left: -22px;     } div.filtered span.lang     {     position: relative;     left: 0px;     } /* --------------------------------------------------               PARAMETER POPUP STYLES -------------------------------------------------- */ div.reftip /* Defines the RefTip popup in Syntax */     {     position: absolute;     z-index: 1;     visibility: hidden;     border: 1px solid #999999;     background: #ffffcc; /*    padding: 0px 0px 0px 0px; */         } div.reftip dl /* Sets margin around the text within the popup */     {     margin: 3px 8px 8px 8px;     } a.synParam /* parameter popup links */     {     color: #0000ff; /* Must match the a:link style color */     text-decoration: underline;     } a.synParam:visited /* ensures parameter popup links are always the unvisited color */     {     color: #0000ff; /* Must match the a:link style color */     text-decoration: underline;     } a.synParam:hover /* parameter popup links */     {     color: #3366ff; /* Must match the a:hover style color */     text-decoration: underline;     font-style: italic;     } /* --------------------------------------------------               EXPAND-COLLAPSE STYLES -------------------------------------------------- */ div.expandBody     {     margin: .5em 0em 0em 1.4em;     display:none;     } a.expandLink1     {     font-size: 115%;      } a#ExPand     {     color: #3366ff;      font-weight: bold;      text-decoration: none;      } a#ExPandAll     {     color: #3366ff;      font-weight: bold;      text-decoration: none;      } /* --------------------------------------------------               GLOSSARY POPUP STYLES            Not used by Visual Studio .NET  -------------------------------------------------- */ /* COMMENT OUT GLOSSARY SECTION /*div#popUpWindow     { Controlled by the script in the variable L_PopUpBoxStyle_Style     }*/ a.glosslink:link     {     color: #000000;     } a.glosslink:visited     {     color: #000000;      } a.glosslink:hover     {     color: #000000;     font-style: italic;     } div#popUpWindow h5 /* Controls the style of the Term in Glossary Popups */     {     margin: 5px 5px 5px 5px;     color: #000000;     } div#popUpWindow p /* Controls the style of the Text in Glossary Popups */     {     margin: 5px 5px 5px 5px;     color: #000000;     } p.GLOSSARY_TEXT     {     } div#popUpWindow a /* Controls the style of the Links in Glossary Popups */     {     } */ /* END COMMENT OUT OF GLOSSARY SECTION */ /* END STYLES REQUIRED BY THE SCRIPT  ================================================== */ </style> <HEAD> <META HTTP-EQUIV="Content-Type" Content="text/html; charset=gb2312"> <TITLE>優(yōu)先級順序</TITLE> <xml> <MSHelp:TOCTitle Title="優(yōu)先級順序"/> <MSHelp:RLTitle Title="優(yōu)先級順序 (JScript .NET)"/> <MSHelp:Keyword Index="A" Term="jsreconOrderOfPrecedence"/> <MSHelp:Keyword Index="A" Term="jsreconOrderOfPrecedence"/> <MSHelp:Keyword Index="K" Term="正則表達式, 優(yōu)先級順序"/> <MSHelp:Keyword Index="K" Term="優(yōu)先級, 正則表達式"/> <MSHelp:Keyword Index="K" Term="正則表達式的優(yōu)先級順序"/> <MSHelp:Attr Name="DevLang" Value="JScript"/> <MSHelp:Attr Name="DevLangVers" Value="kbJScript"/> <MSHelp:Attr Name="DocSet" Value="JScript"/> <MSHelp:Attr Name="DocSet" Value="Visual Studio"/> <MSHelp:Attr Name="Product" Value="VS"/> <MSHelp:Attr Name="ProductVers" Value="kbVS700"/> <MSHelp:Attr Name="Technology" Value="ManagedCode"/> <MSHelp:Attr Name="TechnologyVers" Value="kbManagedCode"/> <MSHelp:Attr Name="TopicType" Value="kbArticle"/> <MSHelp:Attr Name="TargetOS" Value="Windows"/> <MSHelp:Attr Name="Locale" Value="kbChineseSimp"/> </xml> <META name="rtfFileName" content="js7reregexp.rtf"> <META NAME="save" CONTENT="history">   <META NAME="msdnID" CONTENT="_731803"> </HEAD> <body topmargin=0 id="bodyID" class = "dtBODY"> <div   class="wppm3vysvbp"   id="nsbanner"> <div   class="wppm3vysvbp"   id="bannerrow1"> <TABLE CLASS="bannerparthead" CELLSPACING=0> <TR ID="hdr"> <TD CLASS="runninghead" nowrap>JScript .NET</TD> <TD CLASS="product" nowrap>&nbsp;</TD> </TR> </TABLE> </div> <div   class="wppm3vysvbp"   id="TitleRow"> <H1 class="dtH1"><A NAME="jsreconorderofprecedence"></A>優(yōu)先級順序</H1> </div></div>  <div   class="wppm3vysvbp"   id="nstext" valign="bottom"> <P>正則表達式從左到右進行計算，并遵循優(yōu)先級順序，這與算術表達式非常類似。</P> <P>下表從最高到最低說明了各種正則表達式運算符的優(yōu)先級順序：</P> <div   id="wppm3vysvbp"   class="tablediv"><table cellspacing="0" class="dtTABLE"> <TR VALIGN="top"> <TH width=40%>運算符</TH> <TH width=60%>說明</TH> </TR> <TR VALIGN="top"> <TD width=40%>\</TD> <TD width=60%>轉義符</TD> </TR> <TR VALIGN="top"> <TD width=40%>(), (?:), (?=), []</TD> <TD width=60%>括號和中括號</TD> </TR> <TR VALIGN="top"> <TD width=40%>*, +, ?, {n}, {n,}, {n,m}</TD> <TD width=60%>限定符</TD> </TR> <TR VALIGN="top"> <TD width=40%>^, $, \<I>anymetacharacter, anycharacter</I></TD> <TD width=60%>定位點和序列</TD> </TR> <TR VALIGN="top"> <TD width=40%>|</TD> <TD width=60%>替換</TD> </TR> </table></div> <P>字符比替換運算符具有更高的優(yōu)先級，這樣使得"m|food"匹配"m"或者"food"。若要匹配"mood"或"food"，請使用括號創(chuàng)建子表達式，從而產(chǎn)生"(m|f)ood"。</P> <H4 class="dtH4">請參見</H4> <P><A HREF="jsreconintroductiontoregularexpressions.htm">正則表達式介紹</A></P>  <div   id="wppm3vysvbp"   class="footer">  <HR> <p><A HREF="JavaScript:sendfeedback('CHS _731803', 'VSDOCS@MICROSOFT.COM')">將文檔反饋發(fā)送給 Microsoft</A></p> <p><MSHelp:link keywords="vxmscCopyright" TABINDEX="0">&copy; 2002 Microsoft Corporation。保留所有權利。</MSHelp:link></p></div>  </div>   </BODY> </HTML>

[Ctrl+A 全選注:引入外部Js需再刷新一下頁面才能執(zhí)行]

普通字符
區(qū)分普通字符與元字符，并說明如何將多個單字符正則表達式組合在一起，以創(chuàng)建更大的表達式。

普通字符包括沒有顯式指定為元字符的所有可打印和不可打印字符。這包括所有大寫和小寫字母、所有數(shù)字、所有標點符號和一些其他符號。

正則表達式的最簡單形式是在搜索字符串中匹配其本身的單個普通字符。例如，單字符模式，如 A，不論出現(xiàn)在搜索字符串中的何處，它總是匹配字母 A。下面是一些單字符正則表達式模式的示例：

/a/
/7/
/M/
可以將許多單字符組合起來以形成大的表達式。例如，以下正則表達式組合了單字符表達式：a、7 和 M。

/a7M/
請注意，沒有串聯(lián)運算符。只須在一個字符后面鍵入另一個字符。
特殊字符
說明轉義符的概念以及如何創(chuàng)建與元字符匹配的正則表達式。

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> <HTML xmlns:MSHelp="http://msdn.microsoft.com/mshelp" DIR="LTR"> <style type="text/css"> /* VERSION 9345 Designed for IE5.x. Optimal in IE 6.x CSS for use with Developer Tools Documentation Localizable definitions: font families font sizes */ /* --------------------------------------------------                   MAIN TOPIC STYLES -------------------------------------------------- */ div.saveHistory     {     behavior:url(#default#savehistory);     text-decoration: underline     } body /* This body tag requires the use of one of the sets of banner and/or text div ids */     {     margin: 0px 0px 0px 0px;     padding: 0px 0px 0px 0px;     background: #ffffff;      color: #000000;     font-family: 瀹嬩綋, Verdana, Arial, Helvetica, sans-serif;     font-size: 75%;     width: 100%;     } div#scrollyes /* Allows topic to scroll with correct margins. Cannot be used with running head banner */     {     /* Must immediately follow <body>. */     padding: 2px 15px 2px 22px;     width: 100%;     } div#nsbanner /* Creates Nonscrolling banner region */     {     position: relative;     left: 0px;     padding: 0px 0px 0px 0px;     border-bottom: 1px solid #999999;     } div#nstext /* Creates the scrolling text area for Nonscrolling region topic */     {     padding: 5px 10px 0px 22px;      } div#scrbanner /* Creates the running head bar in a full-scroll topic */     {     /* Allows topic to scroll. */     margin: 0px 0px 0px 0px;     padding: 0px 0px 0px 0px;     border-bottom: 1px solid #999999;     } div#scrtext /* Creates the text area in a full-scroll topic */     {   /* Allows topic to scroll. */ /*    width: 100%; /* Forces tables to have correct right margin */*/     padding: 0px 10px 0px 22px;      } div#bannerrow1 /* provides full-width color to top row in running head (requires script) */     {     background-color: #99ccff;     } div#titlerow /* provides non-scroll topic title area (requires script) */     {     width: 100%; /* Forces tables to have correct right margin */     padding: 0px 10px 0px 22px;      background-color: #99ccff;             } /* --------------------------------------------------                     HEADING STYLES -------------------------------------------------- */ h1, h2, h3, h4     {     font-family: 瀹嬩綋, Verdana, Arial, Helvetica, sans-serif;     margin-bottom: .4em;      margin-top: 1em;     font-weight: bold;     } h1     {     font-size: 120%;     margin-top: 0em;     } div#scrollyes h1 /* Changes font size for full-scrolling topic */     {     font-size: 150%;     } h2     {     font-size: 120%;     } h3     {     font-size: 115%;     } h4     {     font-size: 100%;     } .dtH1, .dtH2, .dtH3, .dtH4     {     margin-left: -18px;     } div#titlerow h1     {     margin-bottom: .2em     } /* --------------------------------------------------                      TEXT STYLES -------------------------------------------------- */ p     {     margin: .5em 0em .5em 0em;     } blockquote.dtBlock     {     margin: .5em 1.5em .5em 1.5em;     } div#dtHoverText     {     color: #000066;     } .normal     {     margin: .5em 0em .5em 0em;     } .fineprint     {     font-size: 110%; /* 90% of 70% */     } .indent     {     margin: .5em 1.5em .5em 1.5em;     } .topicstatus /* Topic Status Boilerplate class */     {     display: block;     color: red;     } /* --------------------------------------------------                      LABEL STYLES -------------------------------------------------- */ p.label     {     margin-top: 1em;     } p.labelproc     {     margin-top: 1em;     color: #000066;     } /* --------------------------------------------------                     GRAPHIC STYLES -------------------------------------------------- */ img     {     border: none;      } /* --------------------------------------------------                      LIST STYLES -------------------------------------------------- */ ol, ul     {     margin: .5em 0em 0em 2em;      } li     {     margin-bottom: .5em;     } ul p, ol p, dl p     {     margin-left: 0em;     } ul p.label, ol p.label     {     margin-top: .5em;     } /* --------------------------------------------------                DEFINITION LIST STYLES -------------------------------------------------- */ dl     {     margin-top: 0em;      padding-left: 1px; /* Prevents italic-letter descenders from being cut off */     } dd     {     margin-bottom: 0em;       margin-left: 1.5em;      } dt     {     margin-top: .5em;      } /* --------------------------------------------------            CODE, SYNTAX, and REFTIP STYLES -------------------------------------------------- */ pre     {     margin-top: .5em;     margin-bottom: .5em;      } pre, code, .code     {     font: 100% 瀹嬩綋, Courier New, Monospace, Courier;/* This is 100% of 70% */     color: #000066;     } pre b, code b     {     letter-spacing: .1em; /* opens kerning on bold in Syntax/Code */     } pre.syntax     {     font: 100% Courier New, 瀹嬩綋, Monospace, Courier;/* This is 100% of 70% */     background: #cccccc;     padding: 4px 8px;     cursor: text;     margin-top: 1em;     margin-bottom: 1em;      color: #000000;     border-width: 1px;     border-style: solid;     border-color: #999999;     } /* --------------------------------------------------                       LINK STYLES -------------------------------------------------- */ a:link     {     color: #0000ff;     } a:visited     {     color: #0000ff;     } a:hover     {     color: #3366ff;     } /* --------------------------- MSHelp\:link - Help HxLinks --------------------------- */ MSHelp\:link     {     text-decoration: underline;      color: #0000ff;      hoverColor: #3366ff;     filterString: ;     }     A.HxLinkTable /* MSHelp\:link - Table disambiguation elements */     {     } /* --------------------------- MSHelp\:ktable - Help links --------------------------- */ MSHelp\:ktable     {     disambiguator: span;     separator: &nbsp|&#32;     prefix: |&#32;     postfix: &nbsp;     filterString: ;     } div.HxLinkTable     {     width: auto; /* Forces tables to have correct right margins and top spacing */     margin-top: -.4em;     visibility: visible;     } ol div.HxLinkTable, ul div.HxLinkTable     {     margin-top: 0em; /* Forces tables to have correct right margins and top spacing */     } table.HxLinkTable /* Keep in sync with general table settings below */     {     width: auto;     margin-top: 1.5em;     margin-bottom: .3em;     margin-left: -1em;     border-width: 1px 1px 0px 0px;     border-style: solid;     border-color: #999999;     background-color: #999999;      font-size: 100%; /* Text in Table is same size as text outside table */     behavior:url(hxlinktable.htc); /* Attach the behavior to link elements. */     } table.HxLinkTable th, table.HxLinkTable td /* Keep in sync with general table settings below */     {      border-style: solid; /* Creates the cell border and color */     border-width: 0px 0px 1px 1px;     border-style: solid;     border-color: #999999;     padding: 4px 6px;     text-align: left;     } table.HxLinkTable th /* Keep in sync with general table settings below */     {      background: #cccccc; /* Creates the shaded table header row */     vertical-align: bottom;     } table.HxLinkTable td /* Keep in sync with general table settings below */     {     background: #ffffff;     vertical-align: top;     } /* --------------------------------------------------                     TABLE STYLES -------------------------------------------------- */ div.tablediv     {     width: 100%; /* Forces tables to have correct right margins and top spacing */     margin-top: -.4em;     } ol div.tablediv, ul div.tablediv, ol div.HxLinkTable, ul div.HxLinkTable     {     margin-top: 0em; /* Forces tables to have correct right margins and top spacing */     } table.dtTABLE     {     width: 100%; /* Forces tables to have correct right margin */     margin-top: .6em;     margin-bottom: .3em;     border-width: 1px 1px 0px 0px;     border-style: solid;     border-color: #999999;     background-color: #999999;      font-size: 100%; /* Text in Table is same size as text outside table */     } table.dtTABLE th, table.dtTABLE td     {      border-style: solid; /* Creates the cell border and color */     border-width: 0px 0px 1px 1px;     border-style: solid;     border-color: #999999;     padding: 4px 6px;     text-align: left;     } table.dtTABLE th         {      background: #cccccc; /* Creates the shaded table header row */     vertical-align: bottom;     } table.dtTABLE td         {     background: #ffffff;     vertical-align: top;     } /* -------------------------------------------------- ISSUE REPORTING AND MISC LINKS TOPIC FOOTER -------------------------------------------------- */ div.footer     {          } div.footer hr     {     color: #999999;     height: 1px;     } /* --------------------------------------------------              STYLES FOR RUNNING HEADS -------------------------------------------------- */ table.bannerparthead, table.bannertitle /* General values for the Running Head tables */     {     position: relative;     left: 0px;     top: 0px;     padding: 0px 0px 0px 0px;     margin: 0px 0px 0px 0px;     width: 100%;     height: 21px;      border-collapse: collapse;     border-style: solid;     border-width: 0px;     background-color: #99ccff;      font-size: 100%;     } table.bannerparthead td /* General Values for cells in the top row of running head */     {     margin: 0px 0px 0px 0px;     padding: 2px 0px 0px 4px;     vertical-align: middle;     /*border-width: 0px 0px 1px 0px; */     border-width: 0px     border-style: solid;     border-color: #999999;     background: transparent;      /* font-style: normal; */     font-weight: normal;     } table.bannerparthead td.product /* Values for top right cell in running head */     {                       /* Allows for a second text block in the running head */     text-align: right;     padding: 2px 5px 0px 5px;     } table.bannertitle td /* General Values for cells in the bottom row of running head */     {     margin: 0px 0px 0px 0px;     padding: 0px 0px 0px 3px;     vertical-align: middle;     border-width: 0px 0px 1px 0px;     border-style: solid;     border-color: #999999;     background: transparent;     font-weight: bold;     } td.button1 /* Values for button cells */     {     width: 14px;     cursor: hand;     } /* =================================================             STYLES REQUIRED BY THE SCRIPT */ /* --------------------------------------------------                   SAMPLE VIEWER -------------------------------------------------- */ div#smpMgrCell     {     display:none;     } table.SampMgr     {     margin: 0px 0px 0px -22px;     } table.SampMgr td     {     padding-left: 22px;     } /* -------------------------------------------------- RUNNING HEAD BAR POPUP STYLES: See Also, Requirements, MultiLang Filtering -------------------------------------------------- */ div.sapop, div.langMenu /* See Also & Requirements popups */     {     position: absolute;     left: 0px;     z-index: 1;     width: 50%;     padding: 0px 8px 5px 26px;     visibility: hidden;     border: 1px solid #999999; /* Same as all other border colors */     background: #ffffcc;     } div.langMenu /* MultiLang Filter popup */     {     padding: 10px 10px 10px 10px;     } div.langMenu ul     {     list-style-type: none;     padding-left: 5px;     margin-left: 0px;     } .lang, .ilang /* controls the multilang tag styles */     {     color: #333333;     font-family: Verdana, Arial, 瀹嬩綋, Helvetica, sans-serif;     font-size: 80%;     font-weight: normal;     font-style: normal;     } h1 .lang, h1 .ilang      {     font-size: 80%;     } div.filtered     {     margin-top: .6em;     margin-bottom: .6em;     margin-left: -7px;     padding: 0px 0px 0px 6px;     border-left: 1px solid #999999;     background: #ffffff;     } div.filtered h1, div.filtered h2, div.filtered h3, div.filtered h4     {     margin-left: -22px;     } div.filtered span.lang     {     position: relative;     left: 0px;     } /* --------------------------------------------------               PARAMETER POPUP STYLES -------------------------------------------------- */ div.reftip /* Defines the RefTip popup in Syntax */     {     position: absolute;     z-index: 1;     visibility: hidden;     border: 1px solid #999999;     background: #ffffcc; /*    padding: 0px 0px 0px 0px; */         } div.reftip dl /* Sets margin around the text within the popup */     {     margin: 3px 8px 8px 8px;     } a.synParam /* parameter popup links */     {     color: #0000ff; /* Must match the a:link style color */     text-decoration: underline;     } a.synParam:visited /* ensures parameter popup links are always the unvisited color */     {     color: #0000ff; /* Must match the a:link style color */     text-decoration: underline;     } a.synParam:hover /* parameter popup links */     {     color: #3366ff; /* Must match the a:hover style color */     text-decoration: underline;     font-style: italic;     } /* --------------------------------------------------               EXPAND-COLLAPSE STYLES -------------------------------------------------- */ div.expandBody     {     margin: .5em 0em 0em 1.4em;     display:none;     } a.expandLink1     {     font-size: 115%;      } a#ExPand     {     color: #3366ff;      font-weight: bold;      text-decoration: none;      } a#ExPandAll     {     color: #3366ff;      font-weight: bold;      text-decoration: none;      } /* --------------------------------------------------               GLOSSARY POPUP STYLES            Not used by Visual Studio .NET  -------------------------------------------------- */ /* COMMENT OUT GLOSSARY SECTION /*div#popUpWindow     { Controlled by the script in the variable L_PopUpBoxStyle_Style     }*/ a.glosslink:link     {     color: #000000;     } a.glosslink:visited     {     color: #000000;      } a.glosslink:hover     {     color: #000000;     font-style: italic;     } div#popUpWindow h5 /* Controls the style of the Term in Glossary Popups */     {     margin: 5px 5px 5px 5px;     color: #000000;     } div#popUpWindow p /* Controls the style of the Text in Glossary Popups */     {     margin: 5px 5px 5px 5px;     color: #000000;     } p.GLOSSARY_TEXT     {     } div#popUpWindow a /* Controls the style of the Links in Glossary Popups */     {     } */ /* END COMMENT OUT OF GLOSSARY SECTION */ /* END STYLES REQUIRED BY THE SCRIPT  ================================================== */ </style> <HEAD> <META HTTP-EQUIV="Content-Type" Content="text/html; charset=gb2312"> <TITLE>特殊字符</TITLE> <xml> <MSHelp:TOCTitle Title="特殊字符"/> <MSHelp:RLTitle Title="特殊字符 (JScript .NET)"/> <MSHelp:Keyword Index="A" Term="jsreconSpecialCharacters"/> <MSHelp:Keyword Index="A" Term="jsreconSpecialCharacters"/> <MSHelp:Keyword Index="K" Term="特殊字符, 搜索"/> <MSHelp:Keyword Index="K" Term="正則表達式, 字符匹配"/> <MSHelp:Keyword Index="K" Term="正則表達式中的字符匹配"/> <MSHelp:Attr Name="DevLang" Value="JScript"/> <MSHelp:Attr Name="DevLangVers" Value="kbJScript"/> <MSHelp:Attr Name="DocSet" Value="JScript"/> <MSHelp:Attr Name="DocSet" Value="Visual Studio"/> <MSHelp:Attr Name="Product" Value="VS"/> <MSHelp:Attr Name="ProductVers" Value="kbVS700"/> <MSHelp:Attr Name="Technology" Value="ManagedCode"/> <MSHelp:Attr Name="TechnologyVers" Value="kbManagedCode"/> <MSHelp:Attr Name="TopicType" Value="kbArticle"/> <MSHelp:Attr Name="TargetOS" Value="Windows"/> <MSHelp:Attr Name="Locale" Value="kbChineseSimp"/> </xml> <META name="rtfFileName" content="js7reregexp.rtf"> <META NAME="save" CONTENT="history">   <META NAME="msdnID" CONTENT="_731805"> </HEAD> <body topmargin=0 id="bodyID" class = "dtBODY"> <div   class="wppm3vysvbp"   id="nsbanner"> <div   class="wppm3vysvbp"   id="bannerrow1"> <TABLE CLASS="bannerparthead" CELLSPACING=0> <TR ID="hdr"> <TD CLASS="runninghead" nowrap>JScript .NET</TD> <TD CLASS="product" nowrap>&nbsp;</TD> </TR> </TABLE> </div> <div   class="wppm3vysvbp"   id="TitleRow"> <H1 class="dtH1"><A NAME="jsreconspecialcharacters"></A>特殊字符</H1> </div></div>  <div   class="wppm3vysvbp"   id="nstext" valign="bottom"> <P>許多元字符要求在試圖匹配它們時特別對待。若要匹配這些特殊字符，必須首先使字符"轉義"，即，將反斜杠字符 (\) 放在它們前面。下表列出了特殊字符以及它們的含義：</P> <div   id="wppm3vysvbp"   class="tablediv"><table cellspacing="0" class="dtTABLE"> <TR VALIGN="top"> <TH width=17%>特殊字符</TH> <TH width=83%>注釋</TH> </TR> <TR VALIGN="top"> <TD width=17%>$</TD> <TD width=83%>匹配輸入字符串結尾的位置。如果設置了 <B>RegExp</B> 對象的 <B>Multiline</B> 屬性，那么 $ 還匹配 \n 或 \r 前面的位置。若要匹配 $ 字符本身，請使用 \$。</TD> </TR> <TR VALIGN="top"> <TD width=17%>( )</TD> <TD width=83%>標記子表達式的開始和結束?？梢圆东@子表達式以供以后使用。若要匹配這兩個字符，請使用 $ 和 $。</TD> </TR> <TR VALIGN="top"> <TD width=17%><B>*</B></TD> <TD width=83%>零次或多次匹配前面的字符或子表達式。若要匹配 * 字符，請使用 \*。</TD> </TR> <TR VALIGN="top"> <TD width=17%><B>+</B></TD> <TD width=83%>一次或多次匹配前面的字符或子表達式。若要匹配 + 字符，請使用 \+。</TD> </TR> <TR VALIGN="top"> <TD width=17%><B>.</B></TD> <TD width=83%>匹配除換行符 \n 之外的任何單個字符。若要匹配 .，請使用 \.。</TD> </TR> <TR VALIGN="top"> <TD width=17%>[ </TD> <TD width=83%>標記中括號表達式的開始。若要匹配 [，請使用 \[。</TD> </TR> <TR VALIGN="top"> <TD width=17%>?</TD> <TD width=83%>零次或一次匹配前面的字符或子表達式，或指示"非貪心"限定符。若要匹配 ? 字符，請使用 \?。</TD> </TR> <TR VALIGN="top"> <TD width=17%>\</TD> <TD width=83%>將下一字符標記為特殊字符、文本、反向引用或八進制轉義符。例如，字符 n 匹配字符 n。\n 匹配換行符。序列 \\ 匹配 \，序列 \( 匹配 (。</TD> </TR> <TR VALIGN="top"> <TD width=17%>^</TD> <TD width=83%>匹配輸入字符串開始處的位置，但在中括號表達式中使用的情況除外，在那種情況下它對字符集求反。若要匹配 ^ 字符本身，請使用 \^。</TD> </TR> <TR VALIGN="top"> <TD width=17%>{</TD> <TD width=83%>標記限定符表達式的開始。若要匹配 {，請使用 \{。</TD> </TR> <TR VALIGN="top"> <TD width=17%>|</TD> <TD width=83%>指出在兩個項之間進行選擇。若要匹配 |，請使用 \|。</TD> </TR> </table></div> <H4 class="dtH4">請參見</H4> <P><A HREF="jsreconintroductiontoregularexpressions.htm">正則表達式介紹</A></P>  <div   id="wppm3vysvbp"   class="footer">  <HR> <p><A HREF="JavaScript:sendfeedback('CHS _731805', 'VSDOCS@MICROSOFT.COM')">將文檔反饋發(fā)送給 Microsoft</A></p> <p><MSHelp:link keywords="vxmscCopyright" TABINDEX="0">&copy; 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