当我加载我的php页面然后自动提交按钮并再次翻页并再次加载？

Question

我使用wamp服务器php我的admin sql，表创建的连接每件事情都很好，我在本地主机上工作，但是再次页面获取加载，不移动光标等，自动提交按钮点击？

这是屏幕截图http://i.imgur.com/QC6RtAg.jpg?1

       <center><form method="post">
       <table border="0" cellspacing="8">
       <tr>
          <td><label><b>*Select Campus:</b></label></td>
             <td>
            <select name="city" id="city">
                <option value="">-Please Select-</option>
                <option value="Isb">Islamabad</option>
                <option value="Abt">Abbotabad</option>
                <option value="wah">Wah</option>
                <option value="Atk">Attock</option>
                <option value="shw">Sahiwal</option>
                <option value="veh">Vehari</option>
                <option value="vir">Virtual</option>
            </select>
            <font color="red"><?php echo @$_GET['campus'];?></font>
       </td>
    </tr>
    <tr>
    <td><label><b>*Name</b></label></td>
    <td><input type="text" name="name" /> 
   <font color="red"><?php echo @$_GET['newname'];?></font>
   <td></tr>
   <br/>
    <tr>
   <td><label><b>*Login</b></label></td>
    <td><input type="text" name="logid"/>
    <font color="red"><?php echo @$_GET['logname'];?></font> 
    <td></tr>
    <br/>
    <tr>
   <td><label><b>*Email Address</b></label></td>
   <td><input type="text"type="require" name="email"/>
   <font color="red"><?php echo @$_GET['emailname'];?></font>
   </td></tr>
   <br/>
   <tr>
   <td><label><b>*Password</b></label></td>
   <td><input type="password" type="require" name="pass"/>
  <font color="red"><?php echo @$_GET['passname'];?></font>
  </td></tr>
 <br/>
 <tr>
<td><label><b>*Retype Password</b></label></td>
<td><input type="password" type="require" name="rpass"/>
<font color="red"><?php echo @$_GET['rpassname'];?></font>
</td></tr>

 </table>
 <table border="0">
 <tr id="bu">
 <td ><input type="submit" id="cl" value="sign up"name="submit"/></td>    </tr>

 </table>
 </form>
 </center>










 <?php
 $conn = mysqli_connect('localhost', 'root' , '','example');
 if(isset($_POST['submit']))<?php
 { 
$campus=$_POST['city'];
$name = $_POST['name'];
$u_id = $_POST['logid'];
$email = $_POST['email'];
$pass = $_POST['pass'];
$rpass = $_POST['rpass'];
if($campus==''){
echo
"<script>window.open('Log.php?campus=Select campus is    Required','_self')    
</script>";
exit();
}
if($name==''){
echo
"<script>window.open('Log.php?newname=Name is Required','_self')   </script>";
 exit();
 if($u_id==''){
echo
"<script>window.open('Log.php?logname=User ID is Required','_self')</script>";
        exit();
   }
   if($email==''){
   echo
  "<script>window.open('Log.php?emailname=Email is Required','_self')      </script>";
   exit();
  }
  if($pass==''){
   echo
   "<script>window.open('Log.php?passname=Password is Required','_self')   </script>";
    exit();
   }
   if($rpass==''){
   echo
   "<script>window.open('Log.php?rpassname=Password is Required','_self')  </script>";
exit();


}


 $sql = "INSERT INTO      student(Campus,User_id,Login,Email,password,Retype_password)    values('$campus','$name','$u_id','$email','$pass','$rpass')";

 if (mysqli_query($conn,$sql) {
echo "New record created successfully";
 print '<script>alert("Successfully Registered!");</script>'; // Prompts   the user
    print '<script>window.location.assign("login.php");</script>'; //   redirects to register.php
}     else {
 echo "Error: " . $sql . "<br>" . $conn->error;
 }$conn->close();
 }
?>