转至：https://my.oschina.net/u/658145/blog/167651
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title> Ajax </title>
<script type="text/javascript">
var xmlHttpReq = null;//XMLHttpRequest对象 // 去除字符串两边空格
String.prototype.trim = function () {
return this.replace(/(^\s*)|(\s*$)/g, "");
} // 创建XMLHttpRequest对象
function createXMLHttpRequest() {
if (window.XMLHttpRequest) {// IE 7.0及以上版本和非IE的浏览器
xmlHttpReq = new XMLHttpRequest();
} else
{
// IE 6.0及以下版本 t
ry { xmlHttpReq = new ActiveXObject("MSXML2.XMLHTTP");
}catch (e) {
try {
xmlHttpReq = new ActiveXObject("Microsoft.XMLHTTP");
}catch (e) {}
}
} if (!xmlHttpReq) {
alert("当前浏览器不支持!");
return null; }
return xmlHttpReq; } //Ajax请求
function tiplist(txt,requestMethod){
var txtValue = txt.value.trim(); if(txtValue!=""){
var parameter = "code="+txtValue+"&str=中文";
var requestURL = "http://127.0.0.1:8080/MyProj/ShowServlet";
xmlHttpReq = createXMLHttpRequest();
if("GET" == requestMethod.trim().toUpperCase()){
xmlHttpReq.open("GET",encodeURI(EncodeURI(requestURL+"?"+parameter)),true);
xmlHttpReq.setRequestHeader("If-Modified-Since","0"); xmlHttpReq.send("null");
}else if("POST" == requestMethod.trim().toUpperCase()){ xmlHttpReq.open("POST",requestURL,true);
xmlHttpReq.setRequestHeader("Content-Type","application/x-www-form-urlencoded;");
xmlHttpReq.send(encodeURI(encodeURI(parameter))); }else{ alert("错误的请求方式！");
return; } xmlHttpReq.onreadystatechange = function(){ if(xmlHttpReq.readyState == 4){
switch(xmlHttpReq.status){ case 200:
//var datas = xmlHttpReq.responseXML.getElementsByTagName("data");
//alert(datas.length); document.getElementById("downlist").innerHTML = xmlHttpReq.responseText;
break; case 400: alert("错误的请求！\nError Code:400!"); break;
case 403: alert("拒绝请求！\nError Code:403!"); break;
case 404: alert("请求地址不存在！\nError Code:404!");
break; case 500: alert("内部错误！\nError Code:500!");
break; case 503: alert("服务不可用！\nError Code:503!");
break; default: alert("请求返回异常！\nError Code:"+xmlHttpReq.status);
break; } } } } } </script> </head> <body>
<input type="text" id="txt"name="txt"value=""onkeyup="tiplist(this,'post');" /><br/><br/>
<divid="downlist"style="width:200px;height:300px;background:gray;"></div> </body> </html>