function changeLanguage( lang ){
    var loc = window.location.toString().replace('#','');
    var getParams = loc.split('?');
    var params = '';
    if(getParams.length>1) params += getParams[1].replace('lang=hu','').replace('lang=en','');
    if(params!='' && params.substring(0,1)!='&') params = '&'+params;
    window.location=getParams[0]+'?lang='+lang+params;
}