menu.js

本程序使用8种不同的方式实现了Huffman编码算法

if (document.getElementById){ 
  document.write('<style type="text/css">.menuitemgroup{display: none;}</style>')
}

function SwitchMenu(obj)
{
  if(document.getElementById)  {
    var el = document.getElementById(obj);
    var title = document.getElementById(obj+'Title');

    if(obj.indexOf("_selected_")==0&&el.style.display == ""){
      //nicolaken: doesn't work :-(
      //title.style.backgroundImage = "url('images/chapter_open.gif')";
      el.style.display = "block";
    }

    if(el.style.display != "block"){ 
      //nicolaken: doesn't work :-(
      //title.style.backgroundImage = 'url([url]images/chapter_open.gif[/url])';
      el.style.display = "block";
    }else{
      //nicolaken: doesn't work :-(
      //title.style.backgroundImage = "url('images/chapter.gif')";
      el.style.display = "none";
    }
  }// end -  if(document.getElementById) 
}//end - function SwitchMenu(obj)