Validation in form create by $fieldset

Question

How to add 2 or more validation in $fieldset when create. Example:

        $fieldset->addField(
        'tax_class_id',
        'select',
        [
            'name' => 'tax_class',
            'label' => __('Tax Class'),
            'title' => __('Tax Class'),
            'class' => 'required-entry',
            'required' => true,
            'values' => 'test',
        ]
    );

And how to know which is the first validation will check. Thanks all.

Answer 1

$fieldset->addField(
    'tax_class_id',
    'select',
    [
        'name' => 'tax_class',
        'label' => __('Tax Class'),
        'title' => __('Tax Class'),
        'class' => 'validate-email validate-digits required-entry', //add multiple classess
        'required' => true,
        'values' => 'test',
    ]
);

The class required-entry always gets first preference then validation is checked in order of classes added. You can try with validate-email validate-digits required-entry. This is reference for available classes.

Answer 2

You may to add new validations to 'class' element separated with gap. E.g.:

$fieldset->addField(
    'tax_class_id',
    'select',
    [
        'name' => 'tax_class',
        'label' => __('Tax Class'),
        'title' => __('Tax Class'),
        'class' => 'required-entry validate-email validate-digits',
        'required' => true,
        'values' => 'test',
    ]
);

More examples you may find in Magento forms, e.g. app\code\core\Mage\Adminhtml\Block\Permissions\User\Edit\Tab\Main.php