Validating form fields

In basic form field validation, do the following:

• Use a cfinput or cftextarea tag.
• Specify a validation type, such as numeric, or multiple types.
• Optionally, specify an error message.
• Optionally, specify a validation technique. (By default, ColdFusion uses onSubmit validation.)
  The following example specifies onBlur validation of a telephone number:

The following information describes considerations for validation in cfinput and cftextarea tags, and show a more complete example.

Validation type considerations

General considerations: Consider the following issues when you determine how to validate form data:

• When you validate form data using onBlur, onSubmit, onServer, or hidden form field validation, you can specify one or more validation types for each field that you validate. For example, you can specify that a field entry is required and that it must be numeric. To specify multiple validation types for onSubmit, onBlur, or onServer validation, specify the type values in a comma-delimited list.
• If you use onBlur, onSubmit, or onServer type validation, you can specify only one error message for each field that you validate. If you use hidden field validation, you can create a custom message for each validation rule (except for range checking).
• In the cfinput tag, most validation type attributes apply only to text or password fields.
  Validation algorithm differences: The underlying validation code used when validating form data can differ depending on the validation technique and the form type. As a result, the algorithms used vary in some instances, including the following:

• The validation algorithms used for date/time values in onSubmit and OnBlur validation are different from those validation algorithms used for all server-side validation techniques.
• The algorithms used for onSubmit and OnBlur validation in Flash can vary from those algorithms used for HTML or XML format, and generally follow simpler rules.
  For detailed information on the validation algorithms used for validation techniques used on the server, see Validating form data using hidden fields.

Validating data in XML skinnable forms

If you create an XML skinnable form and use any skin provided by Adobe, such as the basic.xsl or silver.xsl skin, you can use all form validation techniques that are available for HTML forms. 
If you use a custom skin (XSL file), the available validation techniques depend on the skin. The cf_webroot\CFIDE\scripts\xsl directory contains a _cfformvalidation.xsl file that implements all ColdFusion HTML form validation techniques and supports onBlur, onSubmit, onServer, and hidden form field validation. XML skin writers can include this file in their skin XSLT to implement ColdFusion validation for their skin.

Example: basic form validation

The following form asks for information to use when registering a new user. It checks to make sure that the user enters required information. (Only the telephone number is optional.) It also checks to make sure that the telephone number and e-mail address are properly formatted and that the number to use in a challenge question is in the proper range. This example performs onSubmit validation. It posts back to itself, and dumps the submitted results.