| The Validate Form behavior enables you to require certain form elements to be filled out by the end user. You can specify that text fields must contain data. Furthermore, you can specify what type of data you're looking for. You can ask for a numeric value, which would be appropriate for a ZIP Code or phone number text field. You can also ask for an email address, which will detect the @ sign in data entered into the field. You can also require any data by checking off the Required check box in the Validate Form dialog box, as shown in Figure 19.24. Figure 19.24. Highlight the text field you want to require data for and specify what type of data must be present in the text field.
Unfortunately, you cannot require the end user to answer questions that use radio buttons, check boxes, drop-down menus, or select boxes. If end users try to submit the form without filling out a required text field, they will receive an alert message specifying which form elements they must fill out. You would normally apply the Validate Form action to the <form> tag. | 
