JS中Number()，parseInt()，parseFloat()区别及实例讲解

　　　　//JS区分0和-0
        var num = 123;
        var num = 123.123;
        var num = 0b10;
        var num = 010;
        var num = 0xff;
        var num = 5e2;
        var num = 5e-2;

        var num = NaN;

        console.log('值: ' , num);
        console.log('类型: ' , typeof(num))

        //NaN本身为false
        //其他类型转为数值失败时都为NaN
        console.log(NaN - 100);
        if(NaN){
            console.log('Yes');
        }else{
            console.log('No');
        }

        //NaN
        var a = '123ad';
        //123
        var a = '123';
        //NaN
        var a = 'f3ad';
        //0
        var a = false;
        //1
        var a = true;
        //NaN
        var a = undefined;
        var a = new  ();
        var a = Array(1,23);

        //1e+124
        var a = 10e123;

        //3
        var a = 0b11;

        //255
        var a = 0xff;

        //1.23
        var a = 1.23;

        //0
        var a = '';

        //1200
        var a = '12e2';

        //0
        var a = null;

        //90
        var a = 0132;

        var n = Number(a);
        console.log(n);

        //123
        var a = '123ad';
        //123
        var a = '123';
        //NaN
        var a = 'f3ad';
        //NaN
        var a = false;
        //NaN
        var a = true;
        //NaN
        var a = undefined;
        var a = new  ();

        //13 第一个值
        var a = Array(13,2);

        //3100000能够解析处时正常解析，不能时只返回第一个数字
        var a = 31e5;

        //3
        var a = 0b11;

        //255
        var a = 0xff;

        //1
        var a = 1.23;

        //NaN
        var a = '';

        //12  字符串只返回12e舍弃
        var a = '12e2';

        //NaN
        var a = null;

        //1
        var a = 1.5;

        //90
        var a = 0132;

        var n = parseInt(a);
        console.log(n);

        var a = parseInt("10",2);
        var a = parseInt("FF",16);
        var a = parseInt("10",8);
        console.log(a);

         //123
        var a = '123ad';
        //123
        var a = '123';
        //NaN
        var a = 'f3ad';
        //NaN
        var a = false;
        //NaN
        var a = true;
        //NaN
        var a = undefined;
        var a = new  ();

        //13 第一个值
        var a = Array(13,2);

        //3100000 范围过大将转为科学计数法再大将为Infinity
        var a = 31e5;

        //3
        var a = 0b11;

        //255
        var a = 0xff;

        //1.23
        var a = 1.23;

        //NaN
        var a = '';

        //1200
        var a = '12e2aa';

        //NaN
        var a = null;

        //1.5
        var a = 1.5;

        //90
        var a = 0132;

        //
        var a = 1.113;

        var n = parseFloat(a);
        console.log(n);