For loop Variations in javascript

In this website there are a list of for loop variations. I can understand the usage of for(var i=0, len=arr.length; i<len ;i++) loop (where arr is an array), since the arr.length isnt calculated every step there is marginal performance gain. However what are the advantages of using the other variants? For instance loops like

traditional for loop vs Iterator in Java

Is there any performance testing results available in comparing traditional for loop vs Iterator while traversing a ArrayList,HashMap and other collections?

for-loop and object control

I'm trying to add elements to an array. The elements of the array are of a custom class called variable. In the problematic for loop, it basically adds the last element trying to be added throughout the loop. Any help would be appreciated!

How to loop through and extract property values from a complex object (Array)?

The following snippet is from an opensource poker client written in JQuery. It displays a poker table that has been previously spawned by the poker server. The table is displayed within a div on the page after the page is loaded.

Gathering segmented data via jQuery with FOR loops

Here's my code (what I'm stuck on is after the jump)

For loop while parsing xml in php?

I am trying to create a for loop that will parse out different elements of xml doc using php. It parses when I put the number of the entry in the line: