function getFile(fileName){
    oxmlhttp = null;
    try{
        oxmlhttp = new XMLHttpRequest();
        oxmlhttp.overrideMimeType("text/xml");
    }
    catch(e){
        try{
            oxmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
        }
        catch(e){
            return null;
        }
    }
    if(!oxmlhttp) return null;
    try{
       oxmlhttp.open("GET",fileName,false);
       oxmlhttp.send(null);
    }
    catch(e){
       return null;
    }
    return oxmlhttp.responseText;
}