Comment form – URL detection, hook?

I have built a comment form that contains your standard Name / Email / Website fields. In each <input> I have the name of the field, which disappears onfocus, reappears onblur. It will allow me to hide my labels with css for a cleaner look.

My problem is, since the term “Website” is in the website field, when a comment is posted, wordpress is counting that a valid URL and displaying it as the author link… as you’d expect.

So my question: Is it possible to write something to put in functions.php to make wordpress detect if the field says ‘Website’ to not post a URL, or act as it would if the field were blank?

I dug around in the core files and found this chunk of code (below). It’s from wp-includes/comment-template.php, the function get_comment_author_url_link seems to do the sniffing as to whether what the user submitted is a real URL or not and reformats it.

I don’t know how ‘hooks’ work, so I may be off base here, but is it possible to write something (a hook maybe? 🙂 ) in your functions.php to essentially rewrite get_comment_author_url_link? To get it to include the field ‘Website’ in it’s detection?

/**
 * Retrieves the HTML link of the url of the author of the current comment.
 *
 * $linktext parameter is only used if the URL does not exist for the comment
 * author. If the URL does exist then the URL will be used and the $linktext
 * will be ignored.
 *
 * Encapsulate the HTML link between the $before and $after. So it will appear
 * in the order of $before, link, and finally $after.
 *
 * @since 1.5.0
 * @uses apply_filters() Calls the 'get_comment_author_url_link' on the complete HTML before returning.
 *
 * @param string $linktext The text to display instead of the comment author's email address
 * @param string $before The text or HTML to display before the email link.
 * @param string $after The text or HTML to display after the email link.
 * @return string The HTML link between the $before and $after parameters
 */
function get_comment_author_url_link( $linktext = '', $before = '', $after = '' ) {
	$url = get_comment_author_url();
	$display = ($linktext != '') ? $linktext : $url;
	$display = str_replace( 'http://www.', '', $display );
	$display = str_replace( 'http://', '', $display );
	if ( '/' == substr($display, -1) )
		$display = substr($display, 0, -1);
	$return = "$before<a href='$url' rel='external'>$display</a>$after";
	return apply_filters('get_comment_author_url_link', $return);
}

/**
 * Displays the HTML link of the url of the author of the current comment.
 *
 * @since 0.71
 * @see get_comment_author_url_link() Echoes result
 *
 * @param string $linktext The text to display instead of the comment author's email address
 * @param string $before The text or HTML to display before the email link.
 * @param string $after The text or HTML to display after the email link.
 */
function comment_author_url_link( $linktext = '', $before = '', $after = '' ) {
	echo get_comment_author_url_link( $linktext, $before, $after );
}