function menuFix() {
	var sfEls = document.getElementById("nav").getElementsByTagName("li");
	for (var i=0; i<sfEls.length; i++) {
		sfEls[i].onmouseover=function() {
			this.className+=(this.className.length>0? " ": "") + "show";
		}
		sfEls[i].onmouseout=function() {
			this.className=this.className.replace(new RegExp("( ?|^)show\\b"), "");
		}
	}
var date = new Date(); //日期对象 
var now = "【今天是"; 
now = now + date.getFullYear()+"年"; //读英文就行了 
now = now + (date.getMonth()+1)+"月"; //取月的时候取的是当前月-1如果想取当前月+1就可以了 
now = now + date.getDate()+"日";  
now = now + " "; 
var week; 
switch (date.getDay()){ 
case 1: 
week="星期一"; 
break; 
case 2: 
week="星期二"; 
break; 
case 3: 
week="星期三"; 
break; 
case 4: 
week="星期四"; 
break; 
case 5: 
week="星期五"; 
break; 
case 6: 
week="星期六"; 
break; 
default: 
week="星期天"; 
} 
now = now + week;
//now = now + date.getHours()+"时";
//now = now + date.getMinutes()+"分"; 
//now = now + date.getSeconds()+"秒"; 
var now =now + "】"; 
document.getElementById("nowDiv").innerHTML = now; //div的html是now这个字符串 
setTimeout("show()",1000); //设置过1000毫秒就是1秒，调用show方法 
}

window.onload=menuFix;