JavaScript数组删除重复元素（去重）的方法

1.

var arr=str.split("");
for(var i=;arr.length->i;i++){
    for(var j=i+;j<arr.length;j++){
        if(arr[j]==arr[i]){
            arr.splice(j,);   //删除之后，数组长度随之减少
            j--;
        }
    }
}
//alert(arr.toString());   //生成的字符串由逗号隔开

//arr.join("");  //生成的字符串无分割符
//arr.join("-");  //join方法可指定生成的字符串的分隔符 

2.

Array.prototype.unique = function() {
    var data = [];
    var a = {}; //声明一个对象，javascript的对象可以当哈希表用
    for (var i = 0; i < this.length; i++) {
        if(!a[this[i]]){
            a[this[i]] = true;
            data[data.length] = this[i];
        }
    }
    return data;
};
var a = new Array("5","7","7");
alert(a);
alert(a.unique());  

3.

Array.prototype.del = function(){
   var a = {}, c = [], l = this.length;
   for (var i = 0; i < l; i++) {
     var b = this[i];
     var d = (typeof b) + b;
     if (a[d] === undefined) {
        c.push(b);
        a[d] = 1;
    }
   }
   return c;
}

var arr = [1,2,5,2,7,3,8];
alert(arr.del());