Javascript Array findIndexhh(fn)

Array.prototype.findIndexhh = function(fn){
 for(var i=0;i<this.length;i++){
  var x = fn.call(this,this[i],i,this)
  if(x){/* w  ww. j av  a  2 s  .co  m*/
   return i;
  }
 }
}
var arr = [2,3,4];
var i = arr.findIndexhh(function(v,i,list){
 return v == 3;
});
console.log(i)