var num = parseInt(demo ,radix); //demo 是你要轉(zhuǎn)換的那個數(shù)

var demo =”123”;
var num = parseInt(demo);
console.log(typeof(num) + “:” + num);//number:123

var demo = true;
var num = parseInt(demo);
console.log(typeof(num) + “:” + num);//number: NaN

var demo = false;
var num = parseInt(demo);
console.log(typeof(num) + “:” + num);//number: NaN

var demo = 123.9;
var num = parseInt(demo);
console.log(typeof(num) + “:” + num);//number: 123，直接砍掉小數(shù)非四舍五入

var demo = “10”;
var num = parseInt(demo ,16);
console.log(typeof(num) + “:” + num); //number: 16

var num = parseInt(demo ,radix); //radix 是基底的意思

//1、
parseInt(10,2)//結(jié)果是 2 因?yàn)榘?0看成是二進(jìn)制把它轉(zhuǎn)換成10進(jìn)制得2

//2
var demo = “123abc”;
var num = parseInt(demo);
console.log(typeof(num) + “:” + num);//結(jié)果：number: 123 
//因?yàn)閜arseInt 從數(shù)字類開始看，看到非數(shù)字類為止，返回原來的數(shù)

console.log(parseInt(0.006)) //0
console.log(parseInt(0.0006)) //0
console.log(parseInt(0.00006)) //0
console.log(parseInt(0.000006)) //0
console.log(parseInt(0.0000006)) //6

parseInt(0.0000006)  //0.000006
String(0.0000006);  //6e-7
parseInt(6e-7);  //6
parseInt(0.0000006)  //6

Math.floor(0.00006);  //0
Math.floor(0.000006);  //0
Math.floor(0.0000006);  //0