function qiehuan(num){
        var qhcon;
        var mynav;
		for(var id = 0;id<=11;id++)
		{
		    qhcon = document.getElementById("qh_con"+id);
		    mynav = document.getElementById("mynav"+id);
		    if(qhcon != null && mynav != null)
		    {
			    if(id==num)
			    {
				    qhcon = document.getElementById("qh_con"+id).style.display="block";
				    mynav = document.getElementById("mynav"+id).className="nav_on";
			    }
			    else
			    {
				    document.getElementById("qh_con"+id).style.display="none";
				    document.getElementById("mynav"+id).className="";
			    }
			}
		}
	}