Undefined Index? - php

Question

I'm working on a very simple, very easy contact form and when i did it on a separate page it worked perfectly, but when i added it to the current website it can't get the $_POST i don't know why. here are the codes
$to ="enter email here";
$name = $_POST["name"];
$email = $_POST["email"];
$header = "From " . $name;
$message = $_POST["message"];
$content = "From: ". $name ."<br /> Email: " . $email ."<br /> Message: " . $message;
if(!filter_var($email, FILTER_VALIDATE_EMAIL)){
echo "illegal email";
}
else
{
if (!empty($name) && !empty($message)){
mail($to, $header, $content);
echo"sent <br />";
echo $content;
}else
{
if(empty($email))
{
echo "your email is empty";
}
elseif(empty($name))
{
echo "please enter your name";
}
elseif(empty($message)){
echo "can't send empty messages";
}
}
}
html
<form method="post" action="mail.php">
<table>
<tr>
<td>
Name:
</td>
<td>
<input type="text" name="name" />
</td>
</tr>
<tr>
<td>
Email:
</td>
<td>
<input type="text" name="email"/>
</td>
</tr>
<tr>
<td>
Subject:
</td>
<td>
<input type="text" name="subject"/>
</td>
</tr>
<tr>
<td>
Message: <br /><br/><br/>
</td>
<td>
<textarea style="resize:vertical;" name="message"></textarea>
</td>
</tr>
<tr>
<td>
</td>
<td>
<input type="submit"/>
</td>
</tr>
</table>
</form>
thanks in advance and sorry if its a repeat

Answer 1

Check that the PHP is actually executing by adding something like this to the top:
echo "Testing PHP...";
If you do not see that output after submitting a form, check that you are posting the form to the right file. For example, you might need to use:
<form method="post" action="/mail.php">
or
<form method="post" action="/php/mail.php">
...code depending on your website structure.

Answer 2

It's certainly not $_POST that's broken, so it must be something either server related or an error in your code.
Do you have any other PHP on the website your importing the form to? If so you need to make sure that it isn't affecting it in any way.
One more thing to check, it has been reported that a PHP update accidently changed the upload limit size from "8M" to "10MB". Have a scan through your php.ini file and make sure that their isn't any unwanted "MB" instead of "M" in your upload limit.
One final suggestion I can give if you still haven't found the cause after this, is try using:
<?php var_dump($_POST); ?>
which should reveal what's really there.