// retrieve data from dom tree
function getValues( xmlDocument, strTagName )
{
    var xmlTags;
    if( strTagName )
        xmlTags =  xmlDocument.getElementsByTagName( strTagName );
    else
        xmlTags =  xmlDocument.childNodes;
        
    var intLen = xmlTags.length;
    if( !intLen )
        return null;
    else if( intLen == 1 )
    {
        if(xmlTags[ 0 ].firstChild == null)
            return "";
        return xmlTags[ 0 ].firstChild.nodeValue;
    }
    else
    {
        var arrValues = new Array( );
        for( var i = 0; i < intLen; i++ )
        {
            arrValues[ i ] = xmlTags[ i ].firstChild.nodeValue;
        }            
        return arrValues;
    }
}