How can I populate a textarea from a URL?

Question

I am trying to write a script in PHP that can send a message to some user on a forum. So for example, the message form can be formatted like such:

<input>Username Goes Here</input

<textarea>Message Goes Here</textarea>

Luckily I am able to populate the input field from how the URL is formatted. However, I am not so lucky with the textarea part.

How would I be able to populate the textarea field?

The link is formatted as such:

https://live.xbox.com/en-US/Messages?gamertag=gamertag

Where "gamertag" is the recipient

The textarea is formatted as:

<textarea class="compose empty" empty="true">Say something here...</textarea>

Thanks for the help!

Answer 1

Like this :

<textarea class="compose empty" empty="true"><?php echo htmlspecialchars($_REQUEST['gamertag']);?></textarea>

Considering the url is

https://live.xbox.com/en-US/Messages?gamertag=gamertag

You can get the value of gamertag like :

$gamertag = htmlspecialchars($_GET['gamertag']);
$gamertag = htmlspecialchars($_REQUEST['gamertag']);

To include static content :

<textarea class="compose empty" empty="true">Your Verification Code is : <?php echo htmlspecialchars($_REQUEST['gamertag']);?></textarea>

Answer 2

Your website can't cause a user's browser to pre-populate arbitrary fields on a third party site.

Presumably Microsoft provide a mechanism to pre-populate the username field for the purposes of "Contact me" links, but not the message since the positive use cases for that are far fewer and it encourages spammy messages.