$(document).ready(function(){
	if(navigator.userAgent.indexOf("Mac") != -1 && navigator.userAgent.indexOf("Firefox") != -1){ 
		for(var i = 1; i <= 3; i++){
			var tgtClass=$(".topMenuBlock"+i);
			tgtClass.css("background","none");
			tgtClass.empty();
			tgtClass.append("<img src='./images/topMenuReplaceImg"+i+".png' border='0'>");
		}
	}
});