<?xml version="1.0" encoding="windows-1251"?>
<?xml-stylesheet href="chrome://global/skin/" type="text/css"?>


<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">

  <script type="application/x-javascript" src="chrome://poster/content/json.js" />


  
  <script type="application/x-javascript">
   <![CDATA[
      function getthetree() {
         return document.getElementById('tree');
      }
   ]]>
</script>

  
  <tree id="tree" flex="1" >
    <treecols>
      <treecol id="title" label="Название" primary="true" flex="1" />
      <treecol id="path" label="Путь" flex="1" />
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    <treechildren id="tree-children">
        <treeitem>
        <treerow>
          <treecell label="PHP"   />
          <treecell label="programming/php"  />
        </treerow>
      </treeitem>
    </treechildren>
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  <button label="Добавить элемент" oncommand="addSomething()" />

</window>

function addItem(title, path)
{
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  var cell1 = document.createElement('treecell');
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  cell2.setAttribute('label', path);
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  item.appendChild(row);
  document.getElementById('tree-children').appendChild(item);
}

var current = 0;
var items = [
  ['Java', 'programming/java'],
 ...............................................и тд
];
function addSomething()
{
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  current = (current + 1) % items.length;
  //alert(document.getElementById('tree').contentView.rowCount);

}