JavaScript对数组进行随机重排的方法

<script>
var count = 100000,arr = [];
for(var i=0;i<count;i++){
 arr.push(i);
}
//常规方法，sort()
var t = new Date().getTime();
Array.prototype.sort.call(arr,function(a,b){ return Math.random()>.5 ? -1 : 1;});
document.write(arr+'<br/>');
var t1 = new Date().getTime();
document.write(t1-t);
//以下方法效率最高
if (!Array.prototype.shuffle) {
  Array.prototype.shuffle = function() {
    for(var j, x, i = this.length; i; j = parseInt(Math.random()  i), x = this[--i], this[i] = this[j], this[j] = x);
    return this;
  };
}
var t = new Date().getTime();
arr.shuffle();
document.write('<br/>'+arr+'<br/>');
var t1 = new Date().getTime();
document.write(t1-t);
</script>