function display_div(obj,newID,oldID)
{
	var this_a=document.getElementById(obj);
    var pro_a=document.getElementById('pro_a');
    var upro_a=document.getElementById('upro_a');
    
    var new_div=document.getElementById(newID);
    var old_div=document.getElementById(oldID);
	
    //改变a的样式
    if(this_a==pro_a)
    {						
        pro_a.style.fontSize="14px";
		pro_a.style.backgroundColor ="#c5c5c5";
		upro_a.style.fontSize = "12px";
		upro_a.style.backgroundColor = "";      			
    }
    else 
	{						
        upro_a.style.fontSize="14px";
		upro_a.style.backgroundColor="#c5c5c5";
        pro_a.style.fontSize = "12px";
		pro_a.style.backgroundColor="";						
    }
    
    //改变显示的产品栏目
    if(old_div!=null)
    old_div.style.display="none";
    if(new_div!=null)
    new_div.style.display="";
}