Javascript Array remove(dx)

Array.prototype.remove=function(dx)
{
    if(isNaN(dx)||dx>this.length){return false;}
    for(var i=0,n=0;i<this.length;i++)
    {/*from  w  w w. j a  v  a 2 s. c om*/
        if(this[i]!=this[dx])
        {
            this[n++]=this[i];
        }
    }
    this.length-=1;
};

Array.prototype.remove = function(dx) {
 if (isNaN(dx) || dx > this.length) {
  return false;//from   ww  w  .  ja  v  a  2 s .  com
 }
 for (var i = 0, n = 0; i < this.length; i++) {
  if (i != dx) {
   this[n++] = this[i]
  }
 }
 this.length -= 1
}

function GetRandomNum(Min, Max) {
 var Range = Max - Min;
 var Rand = Math.random();
 return (Min + Math.round(Rand * Range));
}

function getQueryString(name) {
 var reg = new RegExp("(^|&)" + name + "=([^&]*)(&|$)", "i");
 var r = window.location.search.substr(1).match(reg);
 if (r != null)
  return unescape(r[2]);
 return null;
}
function preImage(url,callback){
  var img = new Image(); 
     img.src = url;   
    if (img.complete) { 
         callback.call(img);
        return; 
     }
     img.onload = function () { 
         callback.call(img);
     };
}