Yes, it's possible, bind jsFunction to load/domready events - via jQuery or Prototype.
Thanks for the reply! Well thats exactly what I did just a little while before your reply!
Called the a4j:jsFunction in the $(document).ready of that particular page. Eg: If my first tab laods page tab1.xhtml then put the call loadTab1() in the $(document).ready defined in tab1.xhtml. Works fine!