$(document).ready(function(){
  $(".navBtn").each(function (){
	 //Grab the src value for each nav button image and remove the '.gif' suffix if src does not contain '_active'
	 var src = $(this).attr('src');
	 if(src.substring(src.length - 11, src.length - 4) != '_active')
	 {

		 src = src.substring(0, src.length - 4);
		 
		 //Add mouse over / mouse off events to change image source
		 $(this).hover( 
				 function() {
					 $(this).attr('src', src + "_active.gif");
				 },
				 function() {
					 $(this).attr('src', src + ".gif");
				 }
		);
		 
	 }

  });
});