标签：检测 this alt null 用户 back etc send erro
输入"root"，OK；输入其它，Error
ajax.jsp
var xhr; function createXhr() { if (window.XMLHttpRequest) { xhr = new XMLHttpRequest(); } else { xhr = new ActiveXObject("Microsoft.XMLHTTP"); } } function chk(elm) { var name = elm.value; createXhr(); xhr.onreadystatechange = callback; xhr.open("get", "AjaxServlet?para="+name, true); xhr.send(null); } function callback() { if (xhr.readyState == 4) { if (xhr.status == 200) { var t = xhr.responseText; //文本 --> Json var json = eval("(" + t + ")"); var elmCmt=document.getElementById("cmt") if(json.result){ elmCmt.innerText="OK"; }else{ elmCmt.innerText="ERR"; } } } }
<body> <input type="text" onblur="chk(this)"> <span id="cmt" style="color:red"></span> <br> <input type="text"> </body>
AjaxServlet.java
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setCharacterEncoding("utf-8"); AhJson aj = new AhJson(); String para=request.getParameter("para"); JSONObject jo = new JSONObject(); if("root".equals(para) ){ jo.put("result", true); }else{ jo.put("result", false); } response.getWriter().write(jo.toString()); }
标签：检测 this alt null 用户 back etc send erro
原文地址：http://www.cnblogs.com/AndyHoo/p/6100049.html
