<DIV ID="LOVE"></DIV>
<SCRIPT LANGUAGE="JavaScript">
<!--
var div_error= document.getElementById('love');
IF (ERROR){
div_error.innerHTML= 'Error message';
}
//-->
</SCRIPT>
<SCRIPT LANGUAGE="JavaScript">
<!--
var div_error= document.getElementById('love');
IF (ERROR){
div_error.innerHTML= 'Error message';
}
//-->
</SCRIPT>
谢谢
客户端用js获取username文本框的失去焦点事件,然后用ajax去数据库查寻并返回结果。
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<META HTTP-EQUIV="expires" CONTENT="0">
<META HTTP-EQUIV="Pragma" CONTENT="no-cache">
<title>PHP+AJAX用户验证</title>
<style type="text/css">
<!--
body{
text-align:center;
font-family: Verdana, Arial, Helvetica, sans-serif;
font-size: 12px;
background:#EFEFEF;
}
#login {
margin-top:6%;
margin-right:auto;
margin-left:auto;
line-height: 20px;
color: #000000;
width:300px;
border:1px solid #336699;
background:#FFF;
}
#frmlogin{
text-align:left;
margin-left:8px;
}
h1{
margin:0px 0px 10px 0px;
padding:0px;
width:100%;
height:30px;
line-height:30px;
color:#FFF;
background:#336699;
font-size:18px;
text-align:left;
text-indent:10px;
font-weight:normal;
font-family:Arial, Helvetica, sans-serif;
}
input{
border:1px solid #336699;
height:14px;
line-height:14px;
width:120px;
}
.button{
padding-right:10px;
padding-left:10px;
height:22px;
line-height:22px;
background:#fbfbfb;
color:#000;
text-align:center;
border-right:2px solid #999;
border-left:2px solid #999;
border-top:1px solid #999;
border-bottom:1px solid #999;
margin-right:5px;
margin-left:5px;
}
label{
font-weight:bold;
color:#336699;
}
#tip{
color:#ff9900;
}
-->
</style>
<script type="text/javascript">
<!--
//XMLHttpRequest
var xmlhttp = false;
function createXMLHttpRequest(){
if (window.XMLHttpRequest) { // Mozilla, Safari, ...
xmlhttp = new XMLHttpRequest();
} else if (window.ActiveXObject) { // IE
xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
}
}
function Ajax(data){
createXMLHttpRequest();
xmlhttp.open("GET","db.php?username="+escape(document.getElementById("username").value),true);
xmlhttp.send(null);
xmlhttp.onreadystatechange=function(){
if (4==xmlhttp.readyState){
if (200==xmlhttp.status){
document.getElementById("tip").innerHTML=xmlhttp.responseText;
}else{
alert("!");
}
}
}
}
function chkUserName(obj){
if(obj.value.length<1){
obj.style.backgroundColor="#efefef";
alert("不能为空!");
obj.focus();
}else{
//Ajax,???
Ajax(obj.value);
} }
//-->
</script>
</head><body>
<div id="login">
<h1>PHP+Ajax</h1>
<form id="frmlogin" name="frmlogin">
<label>用户名:
<input name="username" type="text" id="username" size="22" maxlength="10" onblur="chkUserName(this)" />
</label><label id="tip"></label>
<p>
<label>密 码:
<input name="pwd" type="password" id="pwd" size="24" maxlength="16" />
</label>
</p>
<p align="center">
<input name="Submit" type="button" class="button" id="btn_login" style="width:60px;background:#efefef;height:25px;line-height:25px;font-size:12px;" value="提交" />
<input name="Submit2" type="reset" class="button" style="width:60px;background:#EFEFEF;height:25px;line-height:25px;font-size:12px;" value="重设" />
</p>
</form>
</div>
</body>
</html>/*******************************************************/
db.php <?php
/*数据库连接*/
$conn=@mysql_connect("数据库","名","密码");
mysql_query("SET NAMES UTF8");
mysql_select_db("test_4",$conn);
//设置页面编码
header("Content-type:text/html;charset=UTF-8");
//查询数据库
if(isset($_GET["username"])){
$strsql="SELECT * FROM member WHERE username='".unescape($_GET["username"])."'";
$result=mysql_query($strsql);
$rows=@mysql_num_rows($result);
mysql_close($conn);
//判断是否有此记录
if(!$rows){
echo "此用户名未被注册!";
}else{
echo "已被注册!";
}
}else{
echo "别调戏我!";
}
/*PHP的unescape转换函数,用来转换Javascript用escape函数加密过的字符
--此函数需要iconv函数库支持*/
function unescape($str) {
$str = rawurldecode($str);
preg_match_all("/%u.{4}|&#x.{4};|&#\d+;|&#\d+?|.+/U",$str,$r);
$ar = $r[0];
foreach($ar as $k=>$v) {
if(substr($v,0,2) == "%u")
$ar[$k] = iconv("UCS-2","UTF-8",pack("H4",substr($v,-4)));
elseif(substr($v,0,3) == "&#x")
$ar[$k] = iconv("UCS-2","UTF-8",pack("H4",substr($v,3,-1)));
elseif(substr($v,0,2) == "&#") {
$ar[$k] = iconv("UCS-2","UTF-8",pack("n",preg_replace("/[^\d]/","",$v)));
}
}
return join("",$ar);
}
?>