lib/formslib.php Form Definition

Revision as of 10:21, 3 May 2011 by Mark Johnson (talk | contribs) (Added note to Choosecoursefile to indicate that Moodle 2 now uses filepicker)

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The definition of the elements to be included in the form, their 'types' (PARAM_*), helpbuttons included, etc. is all included in a function you must define in your class.

definition() is used to define the elements in the form and this definition will be used for validating data submitted as well as for printing the form. For select and checkbox type elements only data that could have been selected will be allowed. And only data that corresponds to a form element in the definition will be accepted as submitted data.

The definition() should include all elements that are going to be used on form, some elements may be removed or tweaked later in definition_after_data(). Please do not create conditional elements in definition(), the definition() should not directly depend on the submitted data.

Note that the definition function is called when the form class is instantiated. There is no option to (say) manipulate data in the class (that may affect the rendering of the form) between instantiating the form and calling any other methods.

class simplehtml_form extends moodleform {
    function definition() {
        global $CFG;
        $mform =& $this->_form; // Don't forget the underscore! 
        $mform->addElement()... // Add elements to your form
    }                           // Close the function
}                               // Close the class

Use Fieldsets to group Form Elements

You use code like this to open a fieldset with a legend.
(Note: Some themes turn off legends on admin setting pages by using CSS: #adminsettings legend {display:none;}.)

$mform->addElement('header', 'nameforyourheaderelement', get_string('titleforlegened', 'modulename'));

You can't yet nest these visible fieldsets unfortunately. But in fact groups of elements are wrapped in invisible fieldsets.

You close a fieldset with moodle_form's closeHeaderBefore method. You tell closeHeaderBefore the element before you wish to end the fieldset. A fieldset is automatically closed if you open a new one. You need to use this code only if you want to close a fieldset and the subsequent form elements are not to be enclosed by a visible fieldset (they are still enclosed with an invisibe one with no legend) :



Use the addElement method to add an element to a form. The first few arguments are always the same. The first param is the type of the element to add. The second is the elementname to use which is normally the html name of the element in the form. The third is often the text for the label for the element.

Some examples are below :


$mform->addElement('button', 'intro', get_string("buttonlabel"));

A button element. If you want a submit or cancel button see 'submit' element.


$mform->addElement('checkbox', 'ratingtime', get_string('ratingtime', 'forum'));

This is a simple checkbox. The third parameter for this element is the label to display on the left side of the form. You can also supply a string as a fourth parameter to specify a label that will appear on the right of the element. Checkboxes and radio buttons can be grouped and have individual labels on their right.

You can have a 5th parameter $attributes, as on other elements.


$mform->addElement('advcheckbox', 'ratingtime', get_string('ratingtime', 'forum'), 'Label displayed after checkbox', array('group' => 1), array(0, 1));

Similar to the checkbox above, but with a couple of important improvements:

  1. The 5th parameter is a normal $attributes array, normally used to set HTML attributes for the <input> element. However, a special value of 'group' can be given, which will add a class name to the element, and enable its grouping for a checkbox controller
  2. The 6th parameter is an array of values that will be associated with the checked/unchecked state of the checkbox. With a normal checkbox you cannot choose that value, and in fact an unchecked checkbox will not even be sent with the form data.



$mform->addElement('choosecoursefile', 'mediafile', get_string('mediafile', 'lesson'), array('courseid'=>$COURSE->id));

Choose a file from the course files area. The fourth option is a list of options for the element.

Note: This has been superseded by filepicker in Moodle 2.

array('courseid' =>null,  //if it is null (default then use global $COURSE
      'height'   =>500,   // height of the popup window
      'width'    =>750,   // width of the popup window
      'options'  =>'none'); //options string for the pop up window 
                          //eg. 'menubar=0,location=0,scrollbars,resizable'

You can also pass an optional 5th parameter of attributes, as for other elements. The most useful way of using that is something like

array('maxlength' => 255, 'size' => 48)

to control the maxlength / size of the text box (note size will default to 48 if not specified)

Finally, as this element is a group containing two elements (button + value), you can add validation rules by using the addGroupRule() method in this (complex) way:

$mform->addGroupRule('elementname', array('value' => array(array(list, of, rule, params, but, fieldname))));

Where: "elementname" is the name of the choosecoursefile group element, "value" is the name of the text field within the group and the "list, of, addrule, params, but, fieldname" is exactly that, the list of fields in the normal addRule() function but ommiting the first one, the fieldname.

For example, the file/url resource type, uses one "choosecoursefile" element, and it controls the maximum length of the field (255) with this use of addGroupRule():

$mform->addGroupRule('reference', array('value' => array(array(get_string('maximumchars', '', 255), 'maxlength', 255, 'client'))));


$mform->addElement('date_selector', 'assesstimefinish', get_string('to'));

This is a date selector. You can select a Day, Month and Year using a group of select boxes. The fourth param here is an array of options. The defaults for the options are :

    'startyear' => 1970, 
    'stopyear'  => 2020,
    'timezone'  => 99, 
    'applydst'  => true, 
    'optional'  => false

You can override these defaults by supplying an array as fourth param with one or more keys with a value to override the default. You can supply a fifth param of attributes here as well.


$mform->addElement('date_time_selector', 'assesstimestart', get_string('from'));

This is a group of select boxes to select a date (Day Month and Year) and time (Hour and Minute). When submitted, submitted data is processed and a timestamp is passed to $form->get_data(); the fourth param here is an array of options. The defaults for the options are:

    'startyear' => 1970, 
    'stopyear'  => 2020,
    'timezone'  => 99, 
    'applydst'  => true, 
    'step'      => 5

You can override these defaults by supplying an array as fourth param with one or more keys with a value to override the default. You can supply a fifth param of attributes here as well.


Moodle 2.0

$mform->addElement('duration', 'timelimit', get_string('timelimit', 'quiz'));

This field type lets the user input an interval of time. It comprises a text field, where you can type a number, and a dropdown for selecting a unit (days, hours, minutes or seconds). When submitted the value is converted to a number of seconds.

You can add a fourth parameter to give options. At the moment the only option supported is here is an array of options. The defaults for the options is:

array('optional' => true)

You can also pass an optional 5th parameter of attributes, as for other elements. The most useful way of using that is something like

array('size' => 5)

to control the size of the text box.


File upload input box with browse button. In the form definition type

$mform->addElement('file', 'attachment', get_string('attachment', 'forum'));

after form submission and validation use

if ($data = $mform->get_data()) {

If you need advanced settings such as required file, different max upload size or name of uploaded file

$this->set_upload_manager(new upload_manager('attachment', true, false, $COURSE, false, 0, true, true, false));
            $mform->addElement('file', 'attachment', get_string('attachment', 'forum'));
            $mform->addRule('attachment', null, 'required');
if ($data = $mform->get_data()) {
    $newfilename = $mform->get_new_filename();

When porting old code it is also possible to use the upload manager directly for processing of uploaded files.

Please note that if using set_upload_manager() it must be before addElement('file',..).

Moodle 2.0

File uploading was rewritten in 2.0. Please see inline docs for now. This page will be updated when the new API stabilises.


Moodle 2.0

General replacement of file element.

$mform->addElement('filepicker', 'userfile', get_string('file'), null, array('maxbytes' => $maxbytes, 'accepted_types' => '*'));

See also Using the File API in Moodle forms


$mform->addElement('hidden', 'reply', 'yes');

A hidden element. Set the element name (in this case reply) to the stated value (in this case yes).


You can add arbitrary HTML to your Moodle form:

$mform->addElement('html', '<div class="qheader">');

See "Question: Can I put a moodleform inside a table td?" for a concrete example.

htmleditor & format

$mform->addElement('htmleditor', 'text', get_string('choicetext', 'choice'));
$mform->setType('text', PARAM_RAW);
$mform->addRule('text', null, 'required', null, 'client');
$mform->addElement('format', 'format', get_string('format'));

You can supply a fourth param to htmleditor of an array of options :

    'rows'  => 10, 
    'cols'  => 65, 
    'width' => 0,
    'height'=> 0, 
    'course'=> 0,
//options same as print_textarea params
//use rows and cols options to control htmleditor size.


        $mform->addElement('modgrade', 'scale', get_string('grade'), false);

This is a custom element for selecting a grade for any activity module. The fourth argument is whether to include an option for no grade which has a value 0. This select box does include scales. The default is true, include no grade option.

A helpbutton is automatically added.


         $mform->addElement('password', 'password', get_string('label'), $attributes);

A password element. Fourth param is an array or string of attributes.



         $mform->addElement('passwordunmask', 'password', get_string('label'), $attributes);

A password element with option to show the password in plaintext. Fourth param is an array or string of attributes.


$radioarray[] = &MoodleQuickForm::createElement('radio', 'yesno', '', get_string('yes'), 1, $attributes);
$radioarray[] = &MoodleQuickForm::createElement('radio', 'yesno', '', get_string('no'), 0, $attributes);
$mform->addGroup($radioarray, 'radioar', '', array(' '), false);

Second param names the radio button and should be the same for each button in the group in order to toggle correctly. Third param would be the label for the form element but is generally ignored as this element will always be in a group which has it's own label. Fourth param is a string, a label to be displayed on the right of the element. The fifth is the value for this radio button. $attributes can be a string or an array of attributes.

It is possible to add help to individual radio buttons but this requires a custom template to be defined for the group elements. See MDL-15571.


To set the default for a radio button group as above use the following :

$mform->setDefault('yesno', 0);

This would make the default 'no'.


        $mform->addElement('select', 'type', get_string('forumtype', 'forum'), $FORUM_TYPES, $attributes);

The fourth param for this element is an array of options for the select box. The keys are the values for the option and the value of the array is the text for the option. The fifth param $attributes is optional, see text element for description of attributes param.

It is also possible to create a select with certain options disabled, using this technique.


        $select = &$mform->addElement('select', 'colors', get_string('colors'), array('red', 'blue', 'green'), $attributes);


        $mform->addElement('selectyesno', 'maxbytes', get_string('maxattachmentsize', 'forum'));

If you want a yes / no select box this one automatically translates itself and has value 1 for yes and 0 for no.


         $mform->addElement('static', 'description', get_string('description', 'exercise'),
                  get_string('descriptionofexercise', 'exercise', $COURSE->students));

This is a static element. It should be used with care if it is used to display a static piece of text with a label. The third param is the label and the fourth is the static text itself.

submit, reset and cancel

        //normally you use add_action_buttons instead of this code
        $buttonarray[] = &$mform->createElement('submit', 'submitbutton', get_string('savechanges'));
        $buttonarray[] = &$mform->createElement('reset', 'resetbutton', get_string('revert'));
        $buttonarray[] = &$mform->createElement('cancel');
        $mform->addGroup($buttonarray, 'buttonar', '', array(' '), false);

A 'Submit' type element is a submit type form element which will submit the form. A 'Reset' will not submit the form but will reset any changes the user has made to form contents. A 'Cancel' element cancels form submission. You need to have a branch in your code before you check for get_data() to check if submission has been cancelled with is_cancelled(); See the example on the usage page.

You should name your submit and reset buttons 'submitbutton' and 'resetbutton' or something similar (not 'submit' and 'reset'). This avoids problems in JavaScript of collisions between form element names and names of JavaScript methods of the form object.

add_action_buttons($cancel = true, $submitlabel=null);

You will normally use this helper function which is a method of moodleform to add all the 'action' buttons to the end of your form. A boolean parameter allow you to specify whether to include a cancel button and specify the label for your submit button (pass the result of get_string). Default for the submit button label is get_string('savechanges').


        $mform->addElement('text', 'name', get_string('forumname', 'forum'), $attributes);

For a simple text element. Your fourth parameter here can be a string or array of attributes for the text element. The following are equivalent :


Generally you are encouraged to use CSS instead of using attributes for styling.

A format element can be used as a format select box. It will be non-selectable if you're using an html editor.

The third param for this element is $useHtmlEditor and it defaults to null in which case an html editor is used if the browser and user profile support it.


            $mform->addElement('textarea', 'introduction', get_string("introtext", "survey"), 'wrap="virtual" rows="20" cols="50"');

A textarea element. If you want an htmleditor use htmleditor element. Fourth element here is a string or array of attributes.



            $mform->addElement('recaptcha', 'recaptcha_field_name', $attributes);

Use this recaptcha element to reduce the spam risk in your forms. Third element here is a string or array of attributes. Take care to get an API key from before using this element.

To check whether recaptcha is enabled at site level use:

if (!empty($CFG->recaptchapublickey) && !empty($CFG->recaptchaprivatekey)) {
    //recaptcha is enabled


Moodle 2.0

            $mform->addElement('tags', 'field_name', $lable, $options, $attributes);

Used for editing a list of tags, for example on a blog post.

There is only one option available, 'display', which should be set to one of the contstants MoodleQuickForm_tags::ONLYOFFICIAL, NOOFFICIAL or DEFAULTUI. This controls whether the official tags are listed for easy selection, or a text area where arbitrary tags may be typed, or both. The default is both.

The value should be set/returned as an array of tags.


A 'group' in formslib is just a group of elements that will have a label and will be included on one line.

For example typical code to include a submit and cancel button on the same line :

        $buttonarray[] =& $mform->createElement('submit', 'submitbutton', get_string('savechanges'));
        $buttonarray[] =& $mform->createElement('submit', 'cancel', get_string('cancel'));
        $mform->addGroup($buttonarray, 'buttonar', '', array(' '), false);

You use the same arguments for createElement as you do for addElement. Any label for the element in the third argument is normally ignored (but not in the case of the submit buttons above where the third argument is not for a label but is the text for the button).

Here's a bad example (don't do this for real, use the 'optional' => true option of the date element): putting a date_selector (which is itself a group of elements) and a checkbox on the same line, note that you can disable every element in the group using the group name 'availablefromgroup' but it doesn't disable the controlling element the 'availablefromenabled' checkbox:

	$availablefromgroup[] =& $mform->createElement('date_selector', 'availablefrom', '');
	$availablefromgroup[] =& $mform->createElement('checkbox', 'availablefromenabled', '', get_string('enable'));
        $mform->addGroup($availablefromgroup, 'availablefromgroup', get_string('availablefromdate', 'data'), ' ', false);
        $mform->disabledIf('availablefromgroup', 'availablefromenabled');


        $mform->addRule('elementname', get_string('error'), 'rule type', 'extraruledata', 'server'(default), false, false);

The first param(element) is an element name and second(message) is the error message that will be displayed to the user. The third parameter(type) is the type of rule. The fourth param(format) is used for extra data needed with some rules such as minlength and regex. The fifth parameter(validation) validates input data on server or client side, if validation is done on client side then it will be checked on the server side as well.

 * @param    string     $element       Form element name
 * @param    string     $message       Message to display for invalid data
 * @param    string     $type          Rule type, use getRegisteredRules() to get types
 * @param    string     $format        (optional)Required for extra rule data
 * @param    string     $validation    (optional)Where to perform validation: "server", "client"
 * @param    boolean    $reset         Client-side validation: reset the form element to its original value if there is an error?
 * @param    boolean    $force         Force the rule to be applied, even if the target form element does not exist

Common Rule Types

  • required
  • maxlength
  • minlength
  • rangelength
  • email
  • regex
  • lettersonly
  • alphanumeric
  • numeric
  • nopunctuation
  • nonzero
  • callback
  • compare



            $mform->setHelpButton('lessondefault', array('lessondefault', get_string('lessondefault', 'lesson'), 'lesson'));

First param is an elementname and the second param is an array of params that are passed to helpbutton in weblib.php. Params are :

 * @param string $page  The keyword that defines a help page
 * @param string $title The title of links, rollover tips, alt tags etc
 *           'Help with' (or the language equivalent) will be prefixed and '...' will be stripped.
 * @param string $module Which module is the page defined in
 * @param mixed $image Use a help image for the link?  (true/false/"both")
 * @param boolean $linktext If true, display the title next to the help icon.
 * @param string $text If defined then this text is used in the page, and
 *           the $page variable is ignored.
 * @param boolean $return If true then the output is returned as a string, if false it is printed to the current page.
 * @param string $imagetext The full text for the helpbutton icon. If empty use default help.gif

Make sure you don't set boolean $return to false.

You need to do use this method after addElement();


Moodle 2.0

            $mform->addHelpButton('api_key_field', 'api_key', 'block_extsearch');

In Moodle 2.0 the "setHelpButton" method has been deprecated in favor of the "addHelpButton" method, which has a simplified interface and uses $OUTPUT->help_icon() on the back end. The following parameters are expected:

* @param $elementname The name of the form element to add the help button for
* @param $identifier The identifier for the help string and its title (see below)
* @param $component The component name to look for the help string in

Unlike in Moodle 1.9, it is no longer necessary to put your help pages in separate HTML files. Instead, the function looks for two strings:

1. get_string($identifier, $component): The title of the help page
2. get_string("{$identifier}_help", $component): The content of the help page

So you will need to have $identifier and {$identifier}_help defined in order for the help button to be created properly.


        $mform->addElement('select', 'grade', get_string('gradeforsubmission', 'exercise'), $grades);
        $mform->setHelpButton('grade', array('grade', get_string('gradeforsubmission', 'exercise'), 'exercise'));
        $mform->setDefault('grade', 100);

Set the default of the form value with setDefault($elementname, $value); where elementname is the elementname whose default you want to set and $value is the default to set. We set the defaults for the form in definition(). This default is what is used if no data is loaded into the form with set_data(); eg. on display of the form for an 'add' rather than 'update' function.


For any element or groups of element in a form you can conditionally disable the group or individual element depending on conditions.

You can use $mform->disabledIf($elementName, $dependentOn, $condition = 'notchecked', $value=null)

  • elementname can be a group. If you specify a group all elements in the group will be disabled (if dependentOn is in elementname group that is ignored and not disabled). These are the element names you've used as the second argument in addElement or addGroup.
  • dependentOn is the actual name of the element as it will appear in html. This can be different to the name used in addGroup particularly but also addElement where you're adding a complex element like a date_selector. Check the html of your page. You typically make the depedentOn a checkbox or select box.
  • $condition will be 'notchecked', 'checked', 'noitemselected', 'eq' or, if it is anything else, we test for 'neq'.
    • If $condition is 'eq' or 'neq' then we check the value of the dependentOn field and check for equality (==) or nonequality (!=) in js
    • If $condition is 'checked' or 'notchecked' then we check to see if a checkbox is checked or not.
    • If $condition is 'noitemselected' then we check to see whether nothing is selected in a dropdown list.


// Disable my control unless a checkbox is checked.
$mform->disabledIf('mycontrol', 'somecheckbox');

// Disable my control if a checkbox is checked.
$mform->disabledIf('mycontrol', 'somecheckbox', 'checked');

// Disable my control unless a dropdown has value 42.
$mform->disabledIf('mycontrol', 'someselect', 'eq', 42);

The possible choices here are in the function lockoptionsall in lib/javascript-static.js.


PARAM_* types are used to specify how a submitted variable should be cleaned. These should be used for get parameters such as id, course etc. which are used to load a page and also with setType(); method. Every form element should have a type specified except select, radio box and checkbox elements, these elements do a good job of cleaning themselves (only specified options are allowed as user input).

Most Commonly Used PARAM_* Types

These are the most commonly used PARAM_* types and their proper uses. More types can be seen in moodlelib.php starting around line 100.

  • PARAM_CLEAN is deprecated and you should try to use a more specific type.
  • PARAM_TEXT should be used for cleaning data that is expected to be plain text. It will strip all html tags. But will still let tags for multilang support through.
  • PARAM_NOTAGS should be used for cleaning data that is expected to be plain text. It will strip *all* html type tags. It will still *not* let tags for multilang support through. This should be used for instance for email addresses where no multilang support is appropriate.
  • PARAM_RAW means no cleaning whatsoever, it is used mostly for data from the html editor. Data from the editor is later cleaned before display using format_text() function. PARAM_RAW can also be used for data that is validated by some other way or printed by p() or s().
  • PARAM_INT should be used for integers.
  • PARAM_ACTION is an alias of PARAM_ALPHA and is used for hidden fields specifying form actions.


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