Can't find source of PHP SQL loop - php

Question

Simple question for you guys - I'm trying to submit data to a table in a database and it does so successfully, before continuing to add an infinite number of blank rows to the table.
Here's the code:
<?php
$name = $_POST['name'];
$email = $_POST['email'];
$about = $_POST['about'];
$msg = $_POST['message'];
$con = mysql_connect("DATABASE","USERNAME","PASSWORD");
if (!$con) {
die('Could not connect: ' . mysql_error());
}
$database = mysql_select_db("benpearl_co_uk_db", $con);
if(!$database) {
die('Houston, we have a problem: ' . mysql_error());
}
$sql="INSERT INTO contact (name, email, about, message) VALUES ('$name', '$email', '$about', '$msg')";
if (!mysql_query($sql,$con))
{
die('Error: ' . mysql_error());
}
?>
<script language="JavaScript">
self.location="?email=1";
</script>
Just to reiterate, I have no problem in connecting to the database or successfully putting the values from the form into the table. However once the values are inputted the page continually refreshes, adding blank lines to the table.
What's going wrong with my code here?

Answer 1

You always redirect to the the same page with:
self.location="?email=1";
Try something like:
$sql = "INSERT INTO contact (name, email, about, message) VALUES ('$name', '$email', '$about', '$msg')";
if (mysql_query($sql, $con))
{
header('Location: $other_page');
}
die('Error: ' . mysql_error());

Answer 2

The problem is here:
<script language="JavaScript">
self.location="?email=1";
</script>
Self.location redirects the browser, you are redirecting to the same page with the addition of the url parameter email = 1 which of course runs the script again causing an infinite loop. You should check whether $_POST contains valid values and only then insert into the database.

Answer 3

Well, that's exactly what your code does:
on the server side write a DB row
return page to client, that contains <script language="JavaScript">self.location="?email=1";</script>
which in turn makes the page refresh.
You would need to make the JS part conditional.

Answer 4

you should run the insert only when the button submit is clicked if you have , so even when you load the page again it will not insert again the data
try doing this
if (isset($_POST['submit'])) //then run your insert sql
{
$sql="INSERT INTO contact (name, email, about, message) VALUES ('$name', '$email', '$about', '$msg')";
if (!mysql_query($sql,$con))
{
die('Error: ' . mysql_error());
}
}