function createXMLHttpRequest(){
	var request = false;

	/*@cc_on @*/
	/*@if (@_jscript_version >= 5)
		try {
			request = new ActiveXObject("Msxml2.XMLHTTP");
		} catch (e) {
			try {
				request = new ActiveXObject("Microsoft.XMLHTTP");
			} catch (E) {
				request = false;
			}
		}
	@end @*/

	if (!request && typeof XMLHttpRequest != 'undefined') {
		request = new XMLHttpRequest();
	}
	
	return request;
}

var request = createXMLHttpRequest(); 


function get_username_options_request(username_combo_id) {
	request.open('get', 'rep_xml_request.php?action=' + 'get_usernames'
		+ '&username_combo_id=' + username_combo_id);
	request.setRequestHeader('Content-Type', "text/xml");
	request.onreadystatechange = get_usernames_change; 
	request.send(null);
}

function get_usernames_change(){
	if (request.readyState == 4){ //finished
		var response = request.responseXML.documentElement;i
		
    	var username_combo_id = response.getElementsByTagName('username_combo_id')[0].firstChild.nodeValue;
		var username_combo = document.getElementById(username_combo_id);

		while (username_combo.options.length)
			username_combo.remove(0);

   	var options = response.getElementsByTagName('option');
		var temp_option; 		

		for (i=0; i < options.length; i++) {
			var temp_option = document.createElement('option');		
			temp_option.text = options[i].childNodes[0].nodeValue;
			username_combo.add(temp_option, null); 		
		}
	}
}