// JavaScript Document


var http_request = false;
function send_request(url) {//初始化、指定处理函数、发送请求的函数
	http_request = false;
	//开始初始化XMLHttpRequest对象
	if(window.XMLHttpRequest) { //Mozilla 浏览器
		http_request = new XMLHttpRequest();
		if (http_request.overrideMimeType) {//设置MiME类别
			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) { // 异常，创建对象实例失败
		window.alert("不能创建XMLHttpRequest对象实例.");
		return false;
	}
	http_request.onreadystatechange = processRequest;
	// 确定发送请求的方式和URL以及是否同步执行下段代码
	http_request.open("GET", url, true);
	http_request.send(null);
}