<script language="JavaScript">
function add_elem_to_combo(fcombo, value, text,i)
{
	var parensel= document.getElementById(fcombo);
	var elem = document.createElement("option");
	elem.value = value;
	elem.text = text;
	parensel.options.add(elem);
}


function getComboFromXML(path, combo, xmlStr)
{

// code for IE
		if (window.ActiveXObject)
		  {
		  //Msxml2.DOMDocument
		  xmlDoc=new ActiveXObject("Msxml2.DOMDocument");
		  xmlDoc.async=false;
		  xmlDoc.load(xmlStr);
		  }
		// code for Mozilla, Firefox, Opera, etc.
		else if (document.implementation &&
		document.implementation.createDocument)
		  {
		  xmlDoc=document.implementation.createDocument("","",null);
		  xmlDoc.load(xmlStr);
		  }

		//alert('asd');
		// î÷èùàåì combo
		var selection= document.getElementById(combo);
		selection.options.length =  0 ;
		selection.options[ 0 ]=new Option("----", "", false, false);
		
		var child = 'option'; 
		
		//var oSelct = xml.selectSingleNode(path);
		var oSelct = xmlDoc.documentElement;
		//var oSelct = xmlDoc.getElementsByTagName(child);
		
		if( !oSelct || !oSelct.hasChildNodes() ) return;
		var oNodes;
			var val ;
			var txt ;
		//alert('klp');	
		oNodes = oSelct.selectNodes(child);
		
		for( var j =  0 ; j < oNodes.length; j++ )
		{
			text = oNodes.item(j).attributes( 0 ).value;
			val = oNodes.item(j).attributes( 1 ).value;
			//alert(val);
			//txt = oNodes.item(j).getAttribute("text");
			add_elem_to_combo(combo, val, text,j);
		}

}

 </script>

<select>
  <option text="1-к.кв." value="1" />
  <option text="2-к.кв." value="2" />
  <option text="3-к.кв." value="3" />
</select>

                                         <select name="rub22" id="rub22">
                                                <option value="">Все</option>
                                              </select>
											  
                                              <select name="selecte" OnChange="javascript: getComboFromXML('select', 'rub22', 'select.xml');">
                                                <option value="1"> 1 </option>
                                                <option value="3"> 2 </option>
                                              </select>