PHP返回同一页面，调用header（）函数

Question

Hi I'm making a php page that return to itself when submitting form, but there's a case inside the php that when it's true a header("Location: url") function should be performed.

Is it possible to do so?

        <form action="" method="post">
      <input type="text" name="username" value="" />
        <?php
 if (isset($_POST['submitted'])) {

$username = $_POST['username'];

        $qryS="SELECT * FROM student WHERE ID='$username';";
        $resultS=mysql_query($qryS);
            if($resultS){
            if(mysql_num_rows($resultS)>=1) {

            header("location: studentprofile.php");
            }}
                else {

            echo"<p><small> There was an error</p>";

            }   
}

         ?>
      <input type="submit" name="submitted" value="Submit" /></p>

    </form>

Answer 1

You can not send any headers after you already sent data (HTML). If you move the if-clauses and header() calls to before you output anything - there's no problems.