<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
<script>
//第一种方法
Array.prototype.removeDuplicate = function(){
var n = [];
for(var i=0;i<this.length;i++){
if(n.indexOf(this[i]) == -1 ){
n.push(this[i]);
}
}
return n;
}
var arr = [1,2,3,3,2,‘我‘,‘我‘,34,‘我的‘,NaN,NaN];
var m1 = arr.removeDuplicate();
console.log(m1);//[1, 2, 3, "我", 34, "我的", NaN, NaN]
//第二种方法
Array.prototype.removeDuplicate = function(){
var n = [];
for(var i=0;i<this.length-1;i++){
if(this.indexOf(this[i]) == i){
n.push(this[i]);
}
}
return n;
}
var m2 = arr.removeDuplicate();
console.log(m2);//[1, 2, 3, "我", 34, "我的"]
//第三种方法
Array.prototype.removeDuplicate = function(){
var n = [],m = {};
for(var i=0;i<this.length;i++){
if(!m[this[i]]){
m[this[i]] = true;
n.push(this[i]);
}
}
return n;
}
var m3 = arr.removeDuplicate();
console.log(m3);//[1, 2, 3, "我", 34, "我的", NaN]
//第四种方法
Array.prototype.removeDuplicate = function(){
var n = [];
this.sort();
for(var i=0;i<this.length;i++){
if(this[i] != this[i+1]){
n.push(this[i]);
}
}
return n;
}
var m4 = arr.removeDuplicate();
console.log(m4);//[1, 2, 3, 34, NaN, NaN, "我", "我的"]
</script>
</body>
</html>
原文：http://www.cnblogs.com/binmengxue/p/6198488.html