Return tru, if given value was sent with form data.

Return value

Bool

Arguments

$$key

Form data key name

Full documentation

Add extra value to form data:

$txt .= "<input type=hidden name=tallenna[my_data] />";

function onSaveInit(){
    if ( $this->isFormData('my_data') ){
        // Play with $this->getFormData('my data');
    }
}