var http_request = false;
function createRequest(url) {
	//初始化对象并发出XMLHttpRequest请求
	http_request = false;
	if (window.XMLHttpRequest) { // Mozilla或其他除IE以外的浏览器
		http_request = new XMLHttpRequest();
		if (http_request.overrideMimeType) {
			http_request.overrideMimeType("text/xml");
		}
	} else if (window.ActiveXObject) { // IE浏览器
		try {
			http_request = new ActiveXObject("Msxml2.XMLHTTP");
		} catch (e) {
			try {
				http_request = new ActiveXObject("Microsoft.XMLHTTP");

		   } catch (e) {}
		}
	}
	if (!http_request) {
		alert("不能创建XMLHTTP实例!");
		return false;
	}
	http_request.onreadystatechange = alertContents;    //指定响应方法
	//发出HTTP请求
	http_request.open("GET", url, true);
	http_request.send(null);
}
function alertContents() {    //处理服务器返回的信息
	if (http_request.readyState == 4) {
		if (http_request.status == 200) {
			subType.innerHTML=http_request.responseText;
		} else {
			alert('您请求的页面发现错误');
		}
	}
}

function F_super(val){
	createRequest("share/selSubType.php?brand="+val+'&nocache='+new Date().getTime());  //实现级联下拉列表
}