联级菜单问题


<HEAD>
  <TITLE> New Document </TITLE>
  <META NAME="Generator" CONTENT="EditPlus">
  <META NAME="Author" CONTENT="">
  <META NAME="Keywords" CONTENT="">
  <META NAME="Description" CONTENT="">
<style>
a {
       font-family:Arial, Helvetica, sans-serif;
       font-size:10px;
       color:#666;
       text-decoration:none;
}
a:hover {
       color:#F90;
       text-decoration:underline;
}
a:vistied {
       color:#666;
       text-decoration:none;
}
#tree li {
       color:#666;
       font-size:10px;
       font-family:Arial, Helvetica, sans-serif;
       line-height:180%;
       list-style:none;
}
#tree ul {
       margin-left:16px;
       padding-left:0px;
       display:none;
}
</style>
<script type="text/javascript">
       var lastSubMenuID;
       //记录最后点击的子菜单
       function doRecord(subMenuID) {
              document.getElementById(subMenuID).style.display = "none";
              lastSubMenuID = subMenuID;
       }
       
       //隐藏子菜单
       function hideLastSubMenu() {
              if(lastSubMenuID == undefined || lastSubMenuID == "") {
                     return;
              } else {
                     var lastSubMenu = document.getElementById(lastSubMenuID);
                     lastSubMenu.style.display = "none";
              }
       }
       
       //显示子菜单
       function showSubMenu(subMenuID) {
              if(lastSubMenuID == subMenuID) {
                     if(document.getElementById(lastSubMenuID).style.display == "block") {
                            document.getElementById(lastSubMenuID).style.display = "none";
                            return;
                     }
              }
              
              if(lastSubMenuID == undefined) {
                     doRecord(subMenuID);
              }else{
                     hideLastSubMenu();
                     doRecord(subMenuID);
              }
              changeMenuState(subMenuID);
       }
       
       //改变子菜单的样式
       function changeMenuState(subMenuID) {
              var subMenu = document.getElementById(subMenuID);
              //subMenu.style.filter = "progidXImageTransform.Microsoft.Wipe()";
              //subMenu.filters[0].apply();
              subMenu.style.display = "block";
              //subMenu.filters[0].play();
       }
</script></HEAD>
<BODY>
       <ul id="tree">
       <li id="mainMenu1">
       <a href="#" onClick="showSubMenu('main1SubMenu');">Syringes</a>
              <ul id="main1SubMenu">
                     <li><a href="#" class="link1">Safety Syringes</a></li>
                     <li><a href="#" class="link1">0.1ml Safety...</a></li>
                     <li><a href="#" class="link1">0.5ml Safety...</a></li>
              </ul>
       </li>
       
       <li id="mainMenu2">
       <a href="#" onClick="showSubMenu('main2SubMenu');">Moulds</a>
              <ul id="main2SubMenu">
                     <li><a href="#" class="link1">Hot Runner...</a></li>
                     <li><a href="#" class="link1">Semi-Hot...</a></li>
                     <li><a href="#" class="link1">Cold Runner...</a></li>
              </ul>
       </li>
       
       <li id="mainMenu3">
       <a href="#" onClick="showSubMenu('main3SubMenu');">Moulds</a>
              <ul id="main3SubMenu">
                     <li><a href="#" class="link1">Hot Runner...</a></li>
                     <li><a href="#" class="link1">Semi-Hot...</a></li>
                     <li><a href="#" class="link1">Cold Runner...</a></li>
              </ul>
       </li>
       <li id="mainMenu4">
       <a href="#" onClick="showSubMenu('main4SubMenu');">Moulds</a>
              <ul id="main4SubMenu">
                     <li><a href="#" class="link1">Hot Runner...</a></li>
                     <li><a href="#" class="link1">Semi-Hot...</a></li>
                     <li><a href="#" class="link1">Cold Runner...</a></li>
              </ul>
       </li>
  </ul>
</BODY>请问运行后为什么是树形的？如果要变成横排的该怎么做？jsp