JS去除重复的字符串内容三种方法

String.prototype.repeatOpt = function () {
var str = this + "",objStr = "";
for (var i = 0; i < this.length; i++) {
var s = str[i];
var newStr = str.replace(s, '');
var j = newStr.indexOf(s);
if (j == -1) {
objStr += s;
}
}
return objStr;
}
alert("1,2,2,3,4,4,5,6".repeatOpt());

function filterRepeatStr(str){
var ar2 = str.split(",");
var array = new Array();
var j=0
for(var i=0;i if((array == "" || array.toString().match(new RegExp(ar2[i],"g")) == null)&&ar2[i]!=""){
array[j] =ar2[i];
array.sort();
j++;
}
}
return array.toString();
}