Code working in Chrome but not in Firefox

Question

The following code works in Chrome. But in Firefox the submit step is not working

Answer 1

<?php
if(!isset($_POST['submit'])){
        $id=$_POST['std_no']; // put it here so whenever you click submit button
        echo $id; // $_POST is trigger

?>
<form action="/**input action**/" method="post">
<b>ID:</b>
<input name="std_no" type="text" />
<input type="image" width="100" value="submit" name="submit" id="submit" src="images/butup.gif" alt="submit Button">
</form>

you should input in action=""; // the php page of your code or the page where you want to get the data sample page.php

or try this

<?php echo htmlentities($_SERVER['PHP_SELF']); ?> // put in action

Answer 2

The issue is that an image submit doesn't send the name "submit" it sends "submit_x" and "submit_y"

So you should check for

if (isset($_POST['submit_x']))...

EDIT: I've done a little more testing on this and it appears in Firefox (16) and IE(7, 8, 9) only the x and y get sent whereas in Chrome (23) and Safari (5.1) it also send the name too along with x and y.

So the safest way is to check for the value is : isset($_POST['name_x'])