Notice Post Data HTML Question

[oakhurst]

I need to put a form in a "Notice", as I need to "POST" data to another site. It says that I can use any HTML. I have tested my form code, and post and it works. But when I put it in the VBulletin Notice, it displays as expected, but when I submit the form, it loads the "profile.php" page, and then back to my home page... and the post never reaches the desired site. What is blocking the form post from the Notice?

<form action="http://anysite.com/index.php?user={username}&id={userid}" method="post">
<input name="" type="submit" value="Submit" />
</form>