我吧代码贴出来吧,给你看看
 if(==1){
                tree= document.getElementById(divID);//层ID
                id = document.getElementById(valueID);//被赋值的文本框
                inp = inputID;//引发事件的文本框
                tree.style.width=inp.style.width;
                var root = document.createElement("li");
                root.id = "li_0";
                tree.insertBefore( root );
                root.className = "Opened";
                
                GetSubCategory_callback(response);
                   
                var li100 = document.createElement("li");
                li100.setAttribute("text-align","right");
                li100.setAttribute("margin","0px");
                var a = document.createElement("a");
                a.href = "javascript:void(0);";
                a.innerHTML = "【关闭】";  
                a.onclick=function(){tree.style.display="none";}
                li100.appendChild(a);
               
                var li101 = document.createElement("li");
                var hr = document.createElement("hr");
                hr.size="2px";
                li101.appendChild(hr);
               
                tree.insertBefore( li101 );
                tree.insertBefore( li100 );
                 }
                count++;
                tree.style.display="block";
                tree.onmouseover=function(){clearTimeout(timer)}
        inp.onmouseout=function(){Mout()}