Как сделать проверку полей формы авторизации на HTML5?

[xfvalue_description start="150"]

				if( preg_match( "#\\[xfvalue_{$preg_safe_name} start=['\"](.+?)['\"]\\]#i", $tpl->copy_template, $matches ) ) {
					$count = intval($matches[1]);

					$cut_xfieldsdata = str_replace( "><", "> <", $xfieldsdata[$value[0]] );
					$cut_xfieldsdata = strip_tags( $cut_xfieldsdata, "<br>" );
					$cut_xfieldsdata = trim(str_replace( "<br>", " ", str_replace( "<br />", " ", str_replace( "\n", " ", str_replace( "\r", "", $cut_xfieldsdata ) ) ) ));
					$cut_xfieldsdata = preg_replace('/\s+/u', ' ', $cut_xfieldsdata);

					if( $count AND dle_strlen($cut_xfieldsdata, $config['charset']) > $count ) {
						$cut_xfieldsdata = dle_substr($cut_xfieldsdata, $count, dle_strlen($cut_xfieldsdata, $config['charset']), $config['charset']);
					}

					$tpl->set( $matches[0], $cut_xfieldsdata );
				}