function mune()
{   
    var font = document.getElementById('Div_tab').parentNode.getElementsByTagName('font');
    for( var j=0;j < font.length;j++)
    {
        
	    font[j].onclick = function()
	    {   	
	        setCookie('ShowMenu',this.id);
	        var obj = document.getElementById('Div_tab').parentNode.getElementsByTagName('ul');
            for( var i=0;i < obj.length;i++)
            {   
	            obj[i].style.display = 'none';
            }
            
	        if(this.parentNode.getElementsByTagName('ul')[0].style.display == 'none')
	        {
	           $(this.parentNode.getElementsByTagName('ul')[0]).slideDown(500);
	           this.parentNode.getElementsByTagName('ul')[0].style.display = '';
	        }
	        else
	        {
	            this.parentNode.getElementsByTagName('ul')[0].style.display = 'none';
	        }
	    }	    
    }
        
   
}
function left_daohang_menu()
{        
    var font = document.getElementById('Div_tab').parentNode.getElementsByTagName('ul');
    for( var j=0;j < font.length;j++)
    {
       if(getCookie('ShowMenu')!=null)
       {
            if(j+1==getCookie('ShowMenu'))
           {      	
	            font[j].style.display = '';
           }
           else        
           {        
	            font[j].style.display = 'none';
	       }
       }
       else
       {
           if(j==0)
           {      	
	            font[j].style.display = '';
           }
           else        
           {        
	            font[j].style.display = 'none';
	       }
	   }
    }
	mune();
}

// 获取 Cookie 
function setCookie(name,value)
{
    var Days = 30;
    var exp  = new Date();    //new Date("December 31, 9998");
    exp.setTime(exp.getTime() + Days*24*60*60*1000);
    document.cookie = name + "="+ escape (value) + ";expires=" + exp.toGMTString();
}
function getCookie(name)
{
    var arr,reg=new RegExp("(^| )"+name+"=([^;]*)(;|$)");
    if(arr=document.cookie.match(reg)) return unescape(arr[2]);
    else return null;
}
function delCookie(name)
{
    var exp = new Date();
        exp.setTime(exp.getTime() - 1);
    var cval=getCookie(name);
        if(cval!=null) document.cookie= name + "="+cval+";expires="+exp.toGMTString();
}
<!--
function leftdaohangmenu(obj) { //v3.0
 	 
   for(i=0;i<500;i++)
   {
   	if(document.getElementById("aaa"+i)!=null)
	{
		document.getElementById("aaa"+i).className = "left_menu_off"; 	
	}
	 if(document.getElementById("bbb"+i)!=null)
	{	
		document.getElementById('bbb'+i).className = "a2";	
	}
   }
  
   document.getElementById("aaa"+obj).className = "left_menu_on"; 
   if(document.getElementById("bbb"+obj)!=null)
	{
   	document.getElementById('bbb'+obj).className = "a3";
	}

}
//-->