//定义XMLHttpRequest对象实例
var http_request = false;
//定义可复用的http请求发送函数
function send_request(method,url,content,responseType,callback) {//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;
	}
	if(responseType.toLowerCase()=="text") {
		//http_request.onreadystatechange = processTextResponse;
		http_request.onreadystatechange = callback;
	}
	else if(responseType.toLowerCase()=="xml") {
		//http_request.onreadystatechange = processXMLResponse;
		http_request.onreadystatechange = callback;
	}
	else {
		window.alert("响应类别参数错误。");
		return false;
	}
	// 确定发送请求的方式和URL以及是否异步执行下段代码
	if(method.toLowerCase()=="get") {

		http_request.open(method, url, true);
                http_request.setRequestHeader("If-Modified-Since","0");
	}
	else if(method.toLowerCase()=="post") {
		http_request.open(method, url, true);
		http_request.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
	}
	else {
		window.alert("http请求类别参数错误。");
		return false;
	}
	http_request.send(content);
}


var step=0;
function setTitle(){
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}
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}
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}