Javascript Array shuffle function

This adds shuffle method to array prototype to randomize the order of it's elements

Array.prototype.shuffle = function() {
 	var len = this.length;
	var i = len;
	 while (i--) {
	 	var p = parseInt(Math.random()*len);
		var t = this[i];
  	this[i] = this[p];
  	this[p] = t;
 	}
};
 

Or just as a simple function:

function arrayShuffle(theArray) {
 	var len = theArray.length;
	var i = len;
	 while (i--) {
	 	var p = parseInt(Math.random()*len);
		var t = theArray[i];
  		theArray[i] = theArray[p];
	  	theArray[p] = t;
 	}
};

function arrayShuffle(oldArray) {
	var newArray = oldArray.slice();
 	var len = newArray.length;
	var i = len;
	 while (i--) {
	 	var p = parseInt(Math.random()*len);
		var t = newArray[i];
  		newArray[i] = newArray[p];
	  	newArray[p] = t;
 	}
	return newArray; 
};
 
 

Or as a function that returns a new shuffled array and leaves the original array alone: