JS精確到小數點兩位

1.會四色五入

var num =2.446242342;

num = num.toFixed(2); // 輸出結果為 2.45
2.正則
Number(15.7784514000.toString().match(/^\d+(?:\.\d{0,2})?/))
3.最笨

function get()
{
    var s = 22.127456 + "";
    var str = s.substring(0,s.indexOf(".") + 3);
    alert(str);
}
4.正則
onload = function(){
    var a = "23.456322";
    var aNew;
    var re = /([0-9]+.[0-9]{2})[0-9]*/;
    aNew = a.replace(re,"$1");
    alert(aNew);
}
5.var num=22.127456;
alert( Math.round(num*100)/100);

1.丟棄小數部分,保留整數部分

parseInt(5/2)

2.向上取整,有小數就整數部分加1

Math.ceil(5/2)

3,四舍五入.

Math.round(5/2)

4,向下取整

Math.floor(5/2)