Sets HTML attributes based on element properties.
$element: The renderable element to process.
$map: An associative array whose keys are element property names and whose values are the HTML attribute names to set for corresponding the property; e.g., array('#propertyname' => 'attributename'). If both names are identical except for the leading '#', then an attribute name value is sufficient and no property name needs to be specified.
function element_set_attributes(array &$element, array $map) {
foreach ($map as $property => $attribute) {
// If the key is numeric, the attribute name needs to be taken over.
if (is_int($property)) {
$property = '#' . $attribute;
}
// Do not overwrite already existing attributes.
if (isset($element[$property]) && !isset($element['#attributes'][$attribute])) {
$element['#attributes'][$attribute] = $element[$property];
}
}
}