Drop Menu - Thủ thuật tạo Drop Menu dọc xổ ngang cho Blogger

<style type="text/css">
.sidebarmenu ul{
margin: 0;
padding: 0;
list-style-type: none;
font: bold 13px Verdana;
width: 200px; /* Độ rộng của menu chính cấp 1 */
border-bottom: 1px solid #ccc;
}
.sidebarmenu ul li{
position: relative;
}
/* Top level menu links style */
.sidebarmenu ul li a{
display: block;
overflow: auto; /*force hasLayout in IE7 */
color: white;
text-decoration: none;
padding: 6px;
border-bottom: 1px solid #778;
border-right: 1px solid #778;
}
.sidebarmenu ul li a:link, .sidebarmenu ul li a:visited, .sidebarmenu ul li a:active{
background-color: #012D58; /* Màu nền của tab (default state)*/
}

.sidebarmenu ul li a:visited{
color: white;
}
.sidebarmenu ul li a:hover{
background-color: black;
}
/*Sub level menu items */
.sidebarmenu ul li ul{
position: absolute;
width: 250px; /* Độ rộng của menu con cấp 2 và 3 */
top: 0;
visibility: hidden;
}
.sidebarmenu a.subfolderstyle{
background: url(http://1.bp.blogspot.com/-Dnx2NMUc_VA/UaoeKUU5oQI/AAAAAAAADNc/8ysOZjddVls/s1600/xo+xuong+blogger.gif) no-repeat 97% 50%;
}
</style>
<script type="text/javascript">
var menuids=["sidebarmenu1"] //ThietKeBlogger.Net
function initsidebarmenu(){
for (var i=0; i<menuids.length; i++){
  var ultags=document.getElementById(menuids[i]).getElementsByTagName("ul")
    for (var t=0; t<ultags.length; t++){
    ultags[t].parentNode.getElementsByTagName("a")[0].className+=" subfolderstyle"
  if (ultags[t].parentNode.parentNode.id==menuids[i]) //if this is a first level submenu
   ultags[t].style.left=ultags[t].parentNode.offsetWidth+"px" //dynamically position first level submenus to be width of main menu item
  else //else if this is a sub level submenu (ul)
    ultags[t].style.left=ultags[t-1].getElementsByTagName("a")[0].offsetWidth+"px" //position menu to the right of menu item that activated it
    ultags[t].parentNode.onmouseover=function(){
    this.getElementsByTagName("ul")[0].style.display="block"
    }
    ultags[t].parentNode.onmouseout=function(){
    this.getElementsByTagName("ul")[0].style.display="none"
    }
    }
  for (var t=ultags.length-1; t>-1; t--){ //ThietKeBlogger.Net
  ultags[t].style.visibility="visible"
  ultags[t].style.display="none"
  }
  }
}
if (window.addEventListener)
window.addEventListener("load", initsidebarmenu, false)
else if (window.attachEvent)
window.attachEvent("onload", initsidebarmenu)

</script>
<div class="sidebarmenu">
<ul id="sidebarmenu1">
<li><a href="#">Menu 1</a></li>

<li><a href="#">Menu 2</a>
  <ul>
  <li><a href="#">Sub Item 2.1</a></li>
  <li><a href="#">Sub Item 2.2</a></li>
  </ul>
</li>
<li><a href="#">Menu 3</a>
  <ul>
  <li><a href="#">Sub Item 3.1</a>
<ul>
    <li><a href="#">Sub menu 3.1.1</a></li>
    <li><a href="#">Sub menu 3.1.2</a></li>
    <li><a href="#">Sub menu 3.1.3</a></li>
    <li><a href="#">Sub menu 3.1.4</a></li>
    </ul>
  </li>
  <li><a href="#">Sub menu 3.2</a>
<ul>
    <li><a href="#">Sub menu 3.2.1</a></li>
    <li><a href="#">Sub menu 3.2.2</a></li>
    <li><a href="#">Sub menu 3.2.3</a></li> 
    </ul>
  </li>
  <li><a href="#">Sub Item 3.3</a>
    <ul>
    <li><a href="#">Sub Item 3.3.1</a></li>
    <li><a href="#">Sub Item 3.3.2</a></li>
    <li><a href="#">Sub Item 3.3.3</a></li>
    <li><a href="#">Sub Item 3.3.4</a></li>
    </ul>
  </li>
</ul>
<li><a href="#">Menu 4</a>
  <ul>
  <li><a href="#">Sub Item 4.1</a>
<ul>
    <li><a href="#">Sub Item 4.1.1</a></li>
    <li><a href="#">Sub Item 4.1.2</a></li>
    <li><a href="#">Sub Item 4.1.3</a></li>
    <li><a href="#">Sub Item 4.1.4</a></li>
    </ul>
  </li>

  <li><a href="#">Sub Item 4.3</a>
<ul>
    <li><a href="#">Sub Item 4.2.1</a></li>
    <li><a href="#">Sub Item 4.2.2</a></li>
    <li><a href="#">Sub Item 4.2.3</a></li>
    <li><a href="#">Sub Item 4.2.4</a></li>
    </ul>
  </li>
  <li><a href="#">Sub Item 4.3</a>
    <ul>
    <li><a href="#">Sub Item 4.3.1</a></li>
    <li><a href="#">Sub Item 4.3.2</a></li>
    <li><a href="#">Sub Item 4.3.3</a></li>
    <li><a href="#">Sub Item 4.3.4</a></li>
    </ul>
  </li>
</ul>
<li><a href="#">Menu End</a></li>
</li></li></ul></div> 

5 - Cuối cùng là thay các trường cho hợp lý theo ý bạn và bấm Lưu   (save Widget) lại.