$(function(){$(".roll").each(function(){this.originalSrc=$(this).attr("src");this.rolloverSrc=this.originalSrc.replace(/(\.gif|\.jpg|\.png)$/,"_on$1");this.rolloverImg=new Image();this.rolloverImg.src=this.rolloverSrc}).hover(function(){$(this).attr("src",this.rolloverSrc)},function(){$(this).attr("src",this.originalSrc)})});