php+js+mysql设计的仿webQQ-<4>登陆和注册

function checkLogin()
{
var xmlhttp;
if (window.XMLHttpRequest)
{// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
if(xmlhttp.overrideMimeType)
{//设置MIME类别
xmlhttp.overrideMimeType("text/xml");
}
}
else
{// code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
var url="checkLogin.php?username="+document.getElementById("username").value+"&pwd="+document.getElementById("pwd").value;
//把用户名和密码传到checkLogin.php进行验证
xmlhttp.open("GET",url,true);
xmlhttp.onreadystatechange=function()
{
if (xmlhttp.readyState==4 && xmlhttp.status==200)
{
document.getElementById("error5").innerHTML="<font color=red size=2px>"+xmlhttp.responseText+"</font>" ;
if(xmlhttp.responseText=="登录成功")
{
window.location.href="myWebChat.php";   //验证成功后跳转到自己的主页

}
}
}

xmlhttp.send(null);
}

<?php
header('Content-Type:text/html;charset=GB2312');
include("conn.php");
$username=$_GET["username"];
$pwd=$_GET["pwd"];
if($username==null||$pwd==null)
{
echo "用户名或密码不能为空！";
}
else
{
$sql="select * from user where email='$username'";
$result = mysql_query($sql);
$num=mysql_num_rows($result);
if($num>0)
{
$row=mysql_fetch_array($result);
if($pwd==$row["pwd"])
{
@session_start();
$_SESSION["email"]=$username;
$statesql="update user set state='在线' where email='".$username."'";  //当用户成功登陆后把状态写入数据库
mysql_query($statesql);
echo "登录成功";
}
else
{
echo "用户名或密码错误！";
}
}
else
{
echo "用户名或密码错误！";
}
}
?>

function checkRegistration()
{
var xmlhttp;
if (window.XMLHttpRequest)
{// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
if(xmlhttp.overrideMimeType)
{//设置MIME类别
xmlhttp.overrideMimeType("text/xml");
}
}
else
{// code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
var url="checkRegistration.php?email="+document.getElementById("email").value+"&nickname="+document.getElementById("nickname").value+
"&pwd="+document.getElementById("password2").value+"&sex="+document.getElementById("sex").value+
"&month="+document.getElementById("month").value+"&day="+document.getElementById("day").value+
"&error1="+document.getElementById("error1").innerHTML+"&error2="+document.getElementById("error2").innerHTML+
"&error3="+document.getElementById("error3").innerHTML+"&error4="+document.getElementById("error4").innerHTML;
xmlhttp.open("GET",url,true);
xmlhttp.onreadystatechange=function()
{
if (xmlhttp.readyState==4 && xmlhttp.status==200)
{
document.getElementById("error6").innerHTML="<font color=green size=2px>"+xmlhttp.responseText+"</font>";
if(xmlhttp.responseText=="注册成功")
{
window.location.href="myWebChat.php";

}
}
}
xmlhttp.send(null);
}

<?php
header('Content-Type:text/html;charset=GB2312');
$error1=$_GET["error1"];
$error2=$_GET["error2"];
$error3=$_GET["error3"];
$error4=$_GET["error4"];
$error1=strlen($error1);
$error2=strlen($error2);
$error3=strlen($error3);
$error4=strlen($error4);
if(($error1==49&&$error2==49&&$error3==49&&$error4==53)||($error1==43&&$error2==43&&$error3==43&&$error4==47)) //仅适合IE和Chrome
{     $email=$_GET["email"];
$nickname=$_GET["nickname"];
$pwd=$_GET["pwd"];
$sex=$_GET["sex"];
$month=$_GET["month"];
$day=$_GET["day"];
include("conn.php");
$sql="insert into user values('$email','$pwd','$nickname','$sex','$month','$day','在线')";
$result=mysql_query("$sql");
if($result)
{
@session_start();
$_SESSION["email"]=$email;
echo "注册成功";
}

}
else
{
echo "请完善注册信息!";

}
?>