javascript 过滤没用的值

Array.prototype.filterArr = function(){
var targArr = this;
var newArr = new Array();
for(var i=0,count=targArr.length;i<count;i++){
//如果数组元素为无意义元素
if(targArr[i]!=null&&targArr[i]!=""&&targArr[i]!="undefined"){
var _tempString_ = newArr.toString();
if(_tempString_.indexOf(targArr[i])<0){
newArr.push(targArr[i]);//植入数组中
}
}
}
return newArr;
}