使用php+ajax实现登录功能教程

php登录源码：
下面是chklogin.php页面代码：
<?php
session_start();
$connect=mysql_connect("127.0.0.1","root","123");
if(!$connect)
{
die('Could not connect: ' . mysql_error());
}
mysql_select_db(design,$connect);
$query="select * from ta_user where user_name ='".$name."'";
$result=mysql_query($query) OR die("Unable to connect to MySQL");
$rows=mysql_fetch_array($result);
if($rows[user_password]==$pwd)
{

header("Location:login_suss.php?name=".$name."");
}
else
{
echo "<table width='235' height='61' border='0' align='center'>";
echo "<tr><td height='29'>用户名或密码错误！</td></tr>";
echo "<tr><td height='29'>请点击<a href='javascript:history.go(-1);'>这儿</a>重新输入！";
echo "</td></tr>";
echo "</table>";

}
?>

登陆验证的AJAX代码示例：

<script language="javascript">
function getXMLHTTPRequest()
{
var xRequest=null;
if (window.XMLHttpRequest)
{
xRequest=new XMLHttpRequest();
}
else if (typeof ActiveXObject != "undefined")
{
xRequest=new ActiveXObject("Microsoft.XMLHTTP");
}
return xRequest;
}
function Ajax(url)
{
AjaxObj = getXMLHTTPRequest();
AjaxObj.onreadystatechange = processRequest;
AjaxObj.open("post",url,true);
AjaxObj.setRequestHeader('Content-type','application/x-www-form-urlencoded');
AjaxObj.send("name"+name);

}
function processRequest()
{

if(AjaxObj.readyState == 4)
{
if(AjaxObj.status == 200)
{
if(AjaxObj.responseText != "")
{
document.getElementById("show").innerHTML="";
//alert(AjaxObj.responseText);

document.getElementById("show").innerHTML=AjaxObj.responseText;

}
}
else
{
alert("您所请求的页面有异常。")
}
}
else
{
document.getElementById("show").innerHTML="Loading......";
}
}
</script>
实际应用中，使用onclick="Ajax(***.php)";调用就行..