//ajax实现的方法，其中参数url为请求的页面(myajax.jsp?name=...&age=...),返回请求响应的字符串
function ajax(url,my) {
	var http_request = false;
	if (window.XMLHttpRequest) { // Mozilla, Safari,...
		http_request = new XMLHttpRequest();
		if (http_request.overrideMimeType) {
			http_request.overrideMimeType("text/xml");
		}
	} else {
		if (window.ActiveXObject) { // IE
			try {
				http_request = new ActiveXObject("Msxml2.XMLHTTP");
			}
			catch (e) {
				try {
					http_request = new ActiveXObject("Microsoft.XMLHTTP");
				}
				catch (e) {
				}
			}
		}
	}
	if (!http_request) {
		alert('如需正常使用本站功能推荐使用IE浏览器！');
		return false;
	}
		var getResponse = function () {
		if (http_request.readyState == 4) {
			if (http_request.status == 200) {
				my(http_request.responseText);
			} else {
				alert('服务器忙，请稍后再试!');
				
			}
		}
	};
	http_request.onreadystatechange = getResponse;
	http_request.open("GET",url,true);
	http_request.setRequestHeader("If-Modified-Since","0");
	http_request.send(null);
}