form_example_tutorial_6_validate

Now we add a handler/function to validate the data entered into the "year of birth" field to make sure it's between the values of 1900 and 2000. If not, it displays an error. The value report is $form_state['values'] (see http://drupal.org/node/144132#form-state).

Notice the name of the function. It is simply the name of the form followed by '_validate'. This is always the name of the default validation function. An alternate list of validation functions could have been provided in $form['#validate'].

See also

form_example_tutorial_6()

File

form_example/form_example_tutorial.inc, line 290

This is the Form API Tutorial from the handbook.

Code

function form_example_tutorial_6_validate($form, &$form_state) {
  $year_of_birth = $form_state['values']['year_of_birth'];
  if ($year_of_birth && ($year_of_birth < 1900 || $year_of_birth > 2000)) {
    form_set_error('year_of_birth', t('Enter a year between 1900 and 2000.'));
  }
}