js中sort()排序的原理

众所周知sort（）可以实现排序，不仅是数字，字符串也可以，那么相比读过sort（）源码的同学不会很多，今天给大家讲解一下原理：

从小到大排序

<script type="text/javascript">

var arr = new Array(6)
arr[0] = "10"
arr[1] = "5"
arr[2] = "40"
arr[3] = "25"
arr[4] = "1000"
arr[5] = "1"
document.write(arr.sort(function(a, b)
{
return a - b
}))

</script>

从大到小的排序

<script type="text/javascript">

var arr = new Array(6)
arr[0] = "10"
arr[1] = "5"
arr[2] = "40"
arr[3] = "25"
arr[4] = "1000"
arr[5] = "1"
document.write(arr.sort(function(a, b)
{
return a - b
}))

</script>

看下面的代码

window.onload=function(){
        var arr=[2,55,55,1,75,3,9,35,70,166,432,678,32,98];
        var arr2=["George","John","Thomas","James","Adrew","Martin"];
        function arrsort(a,b){
            return a-b;
            }
        console.log(arr.sort(arrsort));  //数字排序需要函数,如果要从大排到小,就return b-a;
        console.log(arr2.sort());  //字母不需要
}