var len = $("#b span").length,  	curindex = 0;$("#leftRun").click(function(){	if(curindex) {		curindex--;	}else{		return;	}	$("#b").animate({     	left: "-" + curindex * 105	}, 300);	$(".ser_nav>span").eq(curindex).mouseover();	   			});$("#rightRun").click(function(){		if(curindex == len - 5) {			return;		}else{			curindex++;		}		$("#b").animate({ 	    	left: "-" + curindex * 105		},300);		$(".ser_nav>span").eq(curindex).mouseover();});