function backdrop_clean_css_identifier

Prepares a string for use as a CSS identifier (element, class, or ID name).

http://www.w3.org/TR/CSS21/syndata.html#characters shows the syntax for valid CSS identifiers (including element names, classes, and IDs in selectors.)

Parameters

$identifier: The identifier to clean.

$filter: An array of string replacements to use on the identifier.

Return value

The cleaned identifier.:

File

core/includes/common.inc, line 4342

Common functions that many Backdrop modules will need to reference.

Code

function backdrop_clean_css_identifier($identifier, $filter = array(' ' => '-', '_' => '-', '/' => '-', '[' => '-', ']' => '')) {
  // By default, we filter using Backdrop's coding standards.
  $identifier = strtr($identifier, $filter);

  // Valid characters in a CSS identifier are:
  // - the hyphen (U+002D)
  // - a-z (U+0030 - U+0039)
  // - A-Z (U+0041 - U+005A)
  // - the underscore (U+005F)
  // - 0-9 (U+0061 - U+007A)
  // - ISO 10646 characters U+00A1 and higher
  // We strip out any character not in the above list.
  $identifier = preg_replace('/[^\x{002D}\x{0030}-\x{0039}\x{0041}-\x{005A}\x{005F}\x{0061}-\x{007A}\x{00A1}-\x{FFFF}]/u', '', $identifier);

  // Identifiers cannot start with a digit, two hyphens, or a hyphen followed by a digit.
  $identifier = preg_replace(array('/^[0-9]/', '/^(-[0-9])|^(--)/'), array('_', '__'), $identifier);

  return $identifier;
}