function handleHttpResponse() {
	if ( xmlHttp.readyState == 4 && xmlHttp.status == 200 ) {
		var xmlDoc = xmlHttp.responseXML;

		document.getElementsByName('id').item(0).disabled = false;
		if ( xmlDoc.documentElement ) {
			var citys    = xmlDoc.getElementsByTagName('city');
			var codes    = xmlDoc.getElementsByTagName('code');

			for( var i=0; i<codes.length; i++ ) {
				document.getElementsByName('id').item(0).options[i] = new Option(citys[i].firstChild.nodeValue, codes[i].firstChild.nodeValue);
				document.getElementsByName('request').item(0).disabled = false;
			}
		} else {
			document.getElementsByName('pref').item(0).options[0].selected = true;
			document.getElementsByName('id').item(0).disabled = true;
			document.getElementsByName('request').item(0).disabled = true;
		}
	}
}

function getAddrss() {
	var pref = document.getElementsByName('pref').item(0).value;

	xmlHttp.open('GET', 'risk.php?mode=list&p=' + encodeURI(pref), true);
	xmlHttp.onreadystatechange = handleHttpResponse;
	xmlHttp.send(null);
}

function getXmlHttpObject() {
	var xmlhttp;
	/*@cc_on
	@if ( @_jscript_version >= 5 )
		try {
			xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
		} catch (e) {
			try {
				xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
			} catch (E) {
				xmlhttp = false;
			}
		}
	@else
		xmlhttp = false;
	@end @*/
	if ( !xmlhttp && typeof XMLHttpRequest != 'undefined' ) {
		try {
			xmlhttp = new XMLHttpRequest();
			xmlhttp.overrideMimeType("text/xml"); 
		} catch (e) {
			xmlhttp = false;
		}
	}
	return xmlhttp;
}

var xmlHttp = getXmlHttpObject();

// document.getElementsByName('pref').item(0).options[0].selected = true;
// document.getElementsByName('id').item(0).disabled = true;
// document.getElementsByName('request').item(0).disabled = true;