function drupal_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

includes/common.inc, line 3992

Code

function drupal_clean_css_identifier($identifier, $filter = array(
    ' ' => '-',
    '_' => '-',
    '/' => '-',
    '[' => '-',
    ']' => '',
)) {
    // Use the advanced drupal_static() pattern, since this is called very often.
    static $drupal_static_fast;
    if (!isset($drupal_static_fast)) {
        $drupal_static_fast['allow_css_double_underscores'] =& drupal_static(__FUNCTION__ . ':allow_css_double_underscores');
    }
    $allow_css_double_underscores =& $drupal_static_fast['allow_css_double_underscores'];
    if (!isset($allow_css_double_underscores)) {
        $allow_css_double_underscores = variable_get('allow_css_double_underscores', FALSE);
    }
    // Preserve BEM-style double-underscores depending on custom setting.
    if ($allow_css_double_underscores) {
        $filter['__'] = '__';
    }
    // By default, we filter using Drupal'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);
    return $identifier;
}