One of the limitations of HTML forms is the inability to define input fields as required. Because this is a particularly important requirement for database applications, ColdFusion lets you require users to enter data in fields. To specify a field as required, you can do either of the following:

• Use the required attribute of the cfinput, cfselect, cftextarea, and cftree tags.
• Use a hidden field that has a name attribute composed of the field name and the suffix _required. You can use this technique with CFML and HTML form tags.

For example, to require that the user enter a value in the FirstName field of a cfinput tag, use the following syntax:

<cfinput type="Text" name="FirstName" size="20" maxlength="35" required="Yes">

To require that the user enter a value in the FirstName field of an HTML input tag, use the following syntax:

<input type="Text" name="FirstName" size="20" maxlength="35">
<input type="hidden" name="FirstName_required">

In either of these examples, if the user leaves the FirstName field empty, ColdFusion rejects the form submittal and returns a message informing the user that the field is required. You can customize the contents of this error message.

If you use a required attribute, you customize the message by using the message attribute, as follows:

<cfinput type="Text" name="FirstName" size="20" maxlength="35" required="Yes"
    message="You must enter your first name.">

If you use a hidden field tag, you customize the message using the value attribute of the hidden field, as follows:

<input type="hidden" name="FirstName_required"
    value="You must enter your first name.">