Speed test for looping through array (trick from PHP)

programming flash
1

Hi, so on the PHP site it was advised to do for loops in a certain way that I have not seen on any recommendations for AS3. I think I found about a 10 times speed increase and I thought I better check that I was not missing something (?) before going through my code and changing it. Very simple and fairly self explanatory (in the faster one the array.length is not calculated every time I think):

import flash.utils.getTimer;
var time:Number;
var myarray:Array = new Array();
myarray.length=2000000;

time=getTimer();
for(var i:uint=0, j:uint=myarray.length;  i<j;  i++)
{}
trace(getTimer()-time);//11

time=getTimer();
for(var k:uint=0;  k<myarray.length;  k++)
{}
trace(getTimer()-time);//112