// Using multiple unit types within one animation.
	$(document).ready(function(){
    $("#hotarrowright").click(function(){
			if($("#hotmsgslist").css("margin-left") != '-1680px')
			{
				$("#hotmsgslist").animate({ 
					marginLeft: "-=840",
				}, 1000 );
			}
			else
			{
				$("#hotmsgslist").animate({ 
					marginLeft: "0",
				}, 1000 );
			}
    });
    $("#hotarrowleft").click(function(){
			if($("#hotmsgslist").css("margin-left") != '0px')
			{
				$("#hotmsgslist").animate({ 
					marginLeft: "+=840",
				}, 1000 );
			}
			else
			{
				$("#hotmsgslist").animate({ 
					marginLeft: "-1680px",
				}, 1000 );
			}
    });
 });