form_clean_id

Prepare an HTML ID attribute string for a form item.

Remove invalid characters and guarantee uniqueness.

Parameters

$id: The ID to clean.

$flush: If set to TRUE, the function will flush and reset the static array which is built to test the uniqueness of element IDs. This is only used if a form has completed the validation process. This parameter should never be set to TRUE if this function is being called to assign an ID to the #ID element.

Return value

The cleaned ID.

Related topics

Form generation

Functions to enable the processing and display of HTML forms.

6 calls to form_clean_id()

File

includes/form.inc, line 2279

Code

function form_clean_id($id = NULL, $flush = FALSE) {
  static $seen_ids = array();

  if ($flush) {
    $seen_ids = array();
    return;
  }
  $id = str_replace(array('][', '_', ' '), '-', $id);

  // Ensure IDs are unique. The first occurrence is held but left alone.
  // Subsequent occurrences get a number appended to them. This incrementing
  // will almost certainly break code that relies on explicit HTML IDs in
  // forms that appear more than once on the page, but the alternative is
  // outputting duplicate IDs, which would break JS code and XHTML
  // validity anyways. For now, it's an acceptable stopgap solution.
  if (isset($seen_ids[$id])) {
    $id = $id . '-' . $seen_ids[$id]++;
  }
  else {
    $seen_ids[$id] = 1;
  }

  return $id;
}