Adding a field with a maximum length
In this recipe, we will define a field that has a maximum length constraint. This could be used when you require concise summary text to be entered, for example, when screen "real estate" is at a premium. Alternatively, it would be useful for situations when the particular column of a database into which the data will be saved only accepts a certain number of characters.
Getting ready
Please refer to the first recipe in this chapter for details on how to prepare a QuickForm web form which is the basis of this recipe.
How to do it...
Add the following code to our form definition in validation_form.php just after the field definition:
$mform->addElement('text', 'mytext2', 'Max length 5');
$mform->addRule('mytext2', 'Max length 5', 'maxlength', 5, 'client');
When we try out this new form element by entering six characters, we are unable to submit the form and our validation warning message is displayed as seen in the following screenshot:
