Using Gravity Forms ‘gform_field_input’ PHP filter

The gform_field_input filter in Gravity Forms allows you to modify the field’s input tag or create custom field types before the input tag is created.


// Apply to all forms
add_filter('gform_field_input', 'my_custom_function', 10, 5);

// Apply to a specific form
add_filter('gform_field_input_123', 'my_custom_function', 10, 5);

// Apply to a specific form and field
add_filter('gform_field_input_123_6', 'my_custom_function', 10, 5);


  • $input (string) – The input tag string to be filtered. Pass an empty string to bypass filtering or change its value to specify a new input tag.
  • $field (Field Object) – The field that this input tag applies to.
  • $value (string) – The default/initial value that the field should be pre-populated with.
  • $entry_id (integer) – The Entry ID when executed from the entry detail screen, otherwise 0.
  • $form_id (integer) – The current Form ID.

More information

See Gravity Forms Docs: gform_field_input


Create a Google Map field

Replace fields with a google_map custom CSS class to create a Google Map field.

add_filter('gform_field_input', 'map_input', 10, 5);

function map_input($input, $field, $value, $lead_id, $form_id) {
    if ($field->cssClass == 'google_map') {
        $input = '<div class="ginput_container"><iframe width="300" height="300" frameborder="0" scrolling="no" marginheight="0" marginwidth="0" src=",-95.712891&spn=20.981197,26.367188&z=4&output=embed"></iframe><br /><small><a href=",-95.712891&spn=20.981197,26.367188&z=4&source=embed" style="color:#0000FF;text-align:left">View Larger Map</a></small></div>';
    return $input;

Create a hidden field with a custom name

Create a hidden field on the form using a specific name. Note that Gravity Forms won’t save the value during form submission if you use a custom name attribute.

add_filter('gform_field_input', 'tracker', 10, 5);

function tracker($input, $field, $value, $lead_id, $form_id) {
    if ($form_id == 23 && $field->id == 11) {
        $input = '<input type="hidden" id="hidTracker" name="hidTracker" value="test">';
    return $input;