function menu_display(show_id){//显示隐藏程序
  var menus = document.getElementsByName("leftmenu");
  var submenus = document.getElementsByName("submenus");
  var on_img="img/button_03.gif";//打开时图片
  var off_img="img/button_01.gif";//隐藏时图片
  for(i=0;i<menus.length;i++){
  	if(i==show_id){
  		 if (submenus[i].style.display == "none") {//如果为隐藏状态
    				submenus[i].style.display="";//切换为显示状态
    				menus[i].src=on_img;//换图
  			}else{//否则
    				submenus[i].style.display="none";//切换为隐藏状态
   					menus[i].src=off_img;
  			}//换图
  	}else{
  		submenus[i].style.display="none";
  		menus[i].src = off_img;
  	}
  }
}