php, not allowing spaces being added into a text box?

Question

So far i got if ($_POST["Username"] == "" or (!ereg("^[a-z0-9]", $_POST["Username"])))

I just cant seem to find any code that will stop spaces being acceptable. I need spaces to not be allowed. Can anyone help?

Answer 1

This will strip any leading/trailing spaces from $content & then remove all spaces from the $content

$content = preg_replace("/ +/", " ", trim($content));
$content = str_replace(" ", "", $content);

Answer 2

I assume that you are allowing them on the form page, but not the page that processes the form... as in there is no javascript to disallow entering it on the form.

okay, you're on the right track. The regex you have there will only allow lowercase characters and numbers... and only one character! Try using the [:blank:] regex special character.