先給大家展示下效果圖,然后再給大家擼代碼,效果圖如下所示:
下面寫一個(gè)簡(jiǎn)單的例子,檢測(cè)用戶名是否唯一(直接擼代碼):
前端界面:
<%@ page language="java" contentType="text/html; charset=GB18030" pageEncoding="GB18030"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=GB18030"> <title>檢測(cè)用戶名是否唯一</title> <style type="text/css"> <!-- #toolTip { position:absolute; left:331px; top:39px; width:98px; height:48px; padding-top:45px; padding-left:25px; padding-right:25px; z-index:1; display:none; color:red; background-image: url(images/tooltip.jpg); } --> </style> </head> <body style="margin: 0px;"> <form method="post" action="" name="form1"> <table width="509" height="352" border="0" align="center" cellpadding="0" cellspacing="0" background="images/bg.gif"> <tr> <td height="54"> </td> </tr> <tr> <td height="253" valign="top"> <div style="position:absolute;"> <table width="100%" height="250" border="0" cellpadding="0" cellspacing="0"> <tr> <td width="18%" height="54" align="right" style="color:#8e6723 "><b>用戶名:</b></td> <td width="49%"><input name="username" type="text" id="username" size="32"></td> <td width="33%"><img src="images/checkBt.jpg" width="104" height="23" style="cursor:hand;" onClick="checkUser(form1.username);"></td> </tr> <tr> <td height="51" align="right" style="color:#8e6723 "><b>密碼:</b></td> <td><input name="pwd1" type="password" id="pwd1" size="35"></td> <td rowspan="2"> <div id="toolTip"></div></td> </tr> <tr> <td height="56" align="right" style="color:#8e6723 "><b>確認(rèn)密碼:</b></td> <td><input name="pwd2" type="password" id="pwd2" size="35"></td> </tr> <tr> <td height="55" align="right" style="color:#8e6723 "><b>E-mail:</b></td> <td colspan="2"><input name="email" type="text" id="email" size="45"></td> </tr> <tr> <td> </td> <td colspan="2"><input type="image" name="imageField" src="images/registerBt.jpg"></td> </tr> </table> </div> </td> </tr> <tr> <td> </td> </tr> </table> </form> </body> </html>
AJAX文件:
<script language="javascript"> function createRequest(url) { http_request = false; if (window.XMLHttpRequest) { // 非IE瀏覽器 http_request = new XMLHttpRequest(); //創(chuàng)建XMLHttpRequest對(duì)象 } else if (window.ActiveXObject) { // IE瀏覽器 try { http_request = new ActiveXObject("Msxml2.XMLHTTP"); //創(chuàng)建XMLHttpRequest對(duì)象 } catch (e) { try { http_request = new ActiveXObject("Microsoft.XMLHTTP"); //創(chuàng)建XMLHttpRequest對(duì)象 } catch (e) {} } } if (!http_request) { alert("不能創(chuàng)建XMLHttpRequest對(duì)象實(shí)例!"); return false; } http_request.onreadystatechange = getResult; //調(diào)用返回結(jié)果處理函數(shù) http_request.open('GET', url, true); //創(chuàng)建與服務(wù)器的連接 http_request.send(null); //向服務(wù)器發(fā)送請(qǐng)求 } function getResult() { if (http_request.readyState == 4) { // 判斷請(qǐng)求狀態(tài) if (http_request.status == 200) { // 請(qǐng)求成功,開始處理返回結(jié)果 document.getElementById("toolTip").innerHTML=http_request.responseText; //設(shè)置提示內(nèi)容 document.getElementById("toolTip").style.display="block"; //顯示提示框 } else { // 請(qǐng)求頁(yè)面有錯(cuò)誤 alert("您所請(qǐng)求的頁(yè)面有錯(cuò)誤!"); } } } function checkUser(userName){ if(userName.value==""){ alert("請(qǐng)輸入用戶名!");userName.focus();return; }else{ createRequest('checkUser.jsp?user='+userName.value); } } </script>
jsp文件:
此例并沒有連接數(shù)據(jù)庫(kù),只是用數(shù)組簡(jiǎn)單表示注冊(cè)過的用戶。
<%@ page language="java" import="java.util.*" pageEncoding="GB18030" %> <% String[] userList={"明日科技","mr","mrsoft","wgh"}; //創(chuàng)建一個(gè)一維數(shù)組 String user=new String(request.getParameter("user").getBytes("ISO-8859-1"),"GB18030"); //獲取用戶名 Arrays.sort(userList); //對(duì)數(shù)組排序 int result=Arrays.binarySearch(userList,user); //搜索數(shù)組 if(result>-1){ out.println("很抱歉,該用戶名已經(jīng)被注冊(cè)!"); //
總結(jié)
以上所述是小編給大家介紹的AJAX應(yīng)用實(shí)例之檢測(cè)用戶名是否唯一(實(shí)例代碼),希望對(duì)大家有所幫助,如果大家有任何疑問請(qǐng)給我留言,小編會(huì)及時(shí)回復(fù)大家的。在此也非常感謝大家對(duì)腳本之家網(wǎng)站的支持!
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