// JavaScript Document
var http_request = false;
function send_request(url,form,contant) {//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
	if(form=='get'){
		http_request.open('get', url, true);
		http_request.send(null);
	}else if(form=='post'){		
		http_request.open("POST",url,true);
		http_request.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
		http_request.send(contant);//发送请求
	}
}
//---------------return------------------------------
// 处理返回信息的函数
function processRequest() {
	if (http_request.readyState == 4) { // 判断对象状态
		if (http_request.status == 200) { // 信息已经成功返回，开始处理信息
		
			ajax_do();
			
		} else { //页面不正常
			alert("您所请求的页面有异常。");
		}
	}
}