显示隐藏图片

   function showbigpic()
    {
        document.getElementById("456").style.visibility = "visible";
     
     
    }

    function hidebigpic() {
        clearTimeout(t);
        document.getElementById("456").style.visibility = "hidden";
    }

    function ysshow() {
        t=setTimeout("showbigpic()", 1000);
    }