[Help] Variable URL Input

I have a URL (example http://www.laatedaa.com/albums.php?friendID=xxxxx)

I would like to create an HTML webpage where the person would enter a friendID (the xxxxxxx), and when the person hits a Go! (a button), the numbers will be inputted into the URL and opened in a new window. How can I go about doing this? I am a newbie in HTML and want to learn.

 

It's simple.

HTML page form code:
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<form name="form1" method="post" action="go.php" target="_blank">
Enter Friend ID: <input name="friendid" type="text">
<input type="submit" name="Submit" value="Submit">
</form>
====================================

go.php codes:
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<?
$FriendID = strip_tags($_POST['friendid']);
header("location:http://www.laatedaa.com/albums.php?friendID=$FriendID");
exit();
?>
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