February 9, 2013: Updated to only apply validation on currently submitted page for multi-page forms.
Stop! There's a better way.
This snippet is available as a plugin with Gravity Perks, a suite of over 32 premium Gravity Forms plugins!
The snippet might look daunting but it only requires a quick copy and paste and two simple configurations to get it up and running!
| <?php | |
| /** | |
| * Limit How Many Checkboxes Can Be Checked | |
| * http://gravitywiz.com/2012/06/11/limiting-how-many-checkboxes-can-be-checked/ | |
| */ | |
| class GFLimitCheckboxes { | |
| private $form_id; | |
| private $field_limits; | |
| private $output_script; | |
| function __construct($form_id, $field_limits) { | |
| $this->form_id = $form_id; | |
| $this->field_limits = $this->set_field_limits($field_limits); | |
| add_filter("gform_pre_render_$form_id", array(&$this, 'pre_render')); | |
| add_filter("gform_validation_$form_id", array(&$this, 'validate')); | |
| } | |
| function pre_render($form) { | |
| $script = ''; | |
| $output_script = false; | |
| foreach($form['fields'] as $field) { | |
| $field_id = $field['id']; | |
| $field_limits = $this->get_field_limits($field['id']); | |
| if( !$field_limits // if field limits not provided for this field | |
| || RGFormsModel::get_input_type($field) != 'checkbox' // or if this field is not a checkbox | |
| || !isset($field_limits['max']) // or if 'max' is not set for this field | |
| ) | |
| continue; | |
| $output_script = true; | |
| $max = $field_limits['max']; | |
| $selectors = array(); | |
| foreach($field_limits['field'] as $checkbox_field) { | |
| $selectors[] = "#field_{$form['id']}_{$checkbox_field} .gfield_checkbox input:checkbox"; | |
| } | |
| $script .= "jQuery(\"" . implode(', ', $selectors) . "\").checkboxLimit({$max});"; | |
| } | |
| GFFormDisplay::add_init_script($form['id'], 'limit_checkboxes', GFFormDisplay::ON_PAGE_RENDER, $script); | |
| if($output_script): | |
| ?> | |
| <script type="text/javascript"> | |
| jQuery(document).ready(function($) { | |
| $.fn.checkboxLimit = function(n) { | |
| var checkboxes = this; | |
| this.toggleDisable = function() { | |
| // if we have reached or exceeded the limit, disable all other checkboxes | |
| if(this.filter(':checked').length >= n) { | |
| var unchecked = this.not(':checked'); | |
| unchecked.prop('disabled', true); | |
| } | |
| // if we are below the limit, make sure all checkboxes are available | |
| else { | |
| this.prop('disabled', false); | |
| } | |
| } | |
| // when form is rendered, toggle disable | |
| checkboxes.bind('gform_post_render', checkboxes.toggleDisable()); | |
| // when checkbox is clicked, toggle disable | |
| checkboxes.click(function(event) { | |
| checkboxes.toggleDisable(); | |
| // if we are equal to or below the limit, the field should be checked | |
| return checkboxes.filter(':checked').length <= n; | |
| }); | |
| } | |
| }); | |
| </script> | |
| <?php | |
| endif; | |
| return $form; | |
| } | |
| function validate($validation_result) { | |
| $form = $validation_result['form']; | |
| $checkbox_counts = array(); | |
| // loop through and get counts on all checkbox fields (just to keep things simple) | |
| foreach($form['fields'] as $field) { | |
| if( RGFormsModel::get_input_type($field) != 'checkbox' ) | |
| continue; | |
| $field_id = $field['id']; | |
| $count = 0; | |
| foreach($_POST as $key => $value) { | |
| if(strpos($key, "input_{$field['id']}_") !== false) | |
| $count++; | |
| } | |
| $checkbox_counts[$field_id] = $count; | |
| } | |
| // loop through again and actually validate | |
| foreach($form['fields'] as &$field) { | |
| if(!$this->should_field_be_validated($form, $field)) | |
| continue; | |
| $field_id = $field['id']; | |
| $field_limits = $this->get_field_limits($field_id); | |
| $min = isset($field_limits['min']) ? $field_limits['min'] : false; | |
| $max = isset($field_limits['max']) ? $field_limits['max'] : false; | |
| $count = 0; | |
| foreach($field_limits['field'] as $checkbox_field) { | |
| $count += rgar($checkbox_counts, $checkbox_field); | |
| } | |
| if($count < $min) { | |
| $field['failed_validation'] = true; | |
| $field['validation_message'] = sprintf( _n('You must select at least %s item.', 'You must select at least %s items.', $min), $min ); | |
| $validation_result['is_valid'] = false; | |
| } | |
| else if($count > $max) { | |
| $field['failed_validation'] = true; | |
| $field['validation_message'] = sprintf( _n('You may only select %s item.', 'You may only select %s items.', $max), $max ); | |
| $validation_result['is_valid'] = false; | |
| } | |
| } | |
| $validation_result['form'] = $form; | |
| return $validation_result; | |
| } | |
| function should_field_be_validated($form, $field) { | |
| if( $field['pageNumber'] != GFFormDisplay::get_source_page( $form['id'] ) ) | |
| return false; | |
| // if no limits provided for this field | |
| if( !$this->get_field_limits($field['id']) ) | |
| return false; | |
| // or if this field is not a checkbox | |
| if( RGFormsModel::get_input_type($field) != 'checkbox' ) | |
| return false; | |
| // or if this field is hidden | |
| if( RGFormsModel::is_field_hidden($form, $field, array()) ) | |
| return false; | |
| return true; | |
| } | |
| function get_field_limits($field_id) { | |
| foreach($this->field_limits as $key => $options) { | |
| if(in_array($field_id, $options['field'])) | |
| return $options; | |
| } | |
| return false; | |
| } | |
| function set_field_limits($field_limits) { | |
| foreach($field_limits as $key => &$options) { | |
| if(isset($options['field'])) { | |
| $ids = is_array($options['field']) ? $options['field'] : array($options['field']); | |
| } else { | |
| $ids = array($key); | |
| } | |
| $options['field'] = $ids; | |
| } | |
| return $field_limits; | |
| } | |
| } | |
| new GFLimitCheckboxes(115, array( | |
| 5 => array( | |
| 'min' => 2, | |
| 'max' => 3 | |
| ), | |
| 13 => array( | |
| 'max' => 3 | |
| ) | |
| )); |
How do I install this snippet?
Just copy and paste the code into your theme’s functions.php file.
Do I need to modify this snippet to work with my form?
This snippet now uses a class format. This means you can more easily use it on multiple forms! To instantiate this class you will need to know the form ID, field ID and minimum/maximum number of checkboxes which should be allowed/enforced for that field. It will look something like this:
| new GFLimitCheckboxes(115, array( | |
| 5 => array( | |
| 'min' => 2, | |
| 'max' => 3 | |
| ) | |
| )); |
In template form:
| new GFLimitCheckboxes(FORM_ID, array( | |
| FIELD_ID => array( | |
| 'min' => MIN_NUMBER, | |
| 'max' => MAX_NUMBER | |
| ) | |
| )); |
You can specify multiple checkbox fields on a specific form like so:
| new GFLimitCheckboxes(115, array( | |
| 5 => array( | |
| 'min' => 2, | |
| 'max' => 3 | |
| ), | |
| 13 => array( | |
| 'max' => 3 | |
| ) | |
| )); |
Finally, you can apply this functionality to multiple forms:
| new GFLimitCheckboxes(115, array( | |
| 5 => array( | |
| 'min' => 2, | |
| 'max' => 3 | |
| ), | |
| 13 => array( | |
| 'max' => 3 | |
| ) | |
| )); | |
| new GFLimitCheckboxes(38, array( | |
| 2 => array( | |
| 'min' => 5, | |
| 'max' => 5 | |
| ) | |
| )); |
And that’s it!
You can use a little CSS to style the labels for the disabled checkboxes. Here is an example where I’ve set the color to gray:
input[type="checkbox"]:disabled + label { color: #999; }Did this resource help you do something awesome with Gravity Forms? Then you'll absolutely love Gravity Perks; a suite of 31+ essential add-ons for Gravity Forms with support you can count on.
Just wondering if this code be used to set a limit for the total items checked in a combination of three fields? So limit of 5 total for Field1+Field2+Field3…
Hi Katie, not in the snippet, but spanning limits across multiple checkbox fields is available in the Perk version.
GP Limit Checkboxes