Roger wants to check whether a user has or has not entered data in a text field. How can he perform this validation? O A. Check if the value contains an escape character. OB. Check if the value is the same as the default. Ос. Check if the value is numeric. OD. Check for a null character.​

answer

Explanation:You can use regular expressions to match and validate the text that users enter in cfinput and cftextinput tags. Ordinary characters are combined with special characters to define the match pattern. The validation succeeds only if the user input matches the pattern.

Regular expressions let you check input text for a wide variety of custom conditions for which the input must follow a specific pattern. You can concatenate simple regular expressions into complex search criteria to validate against complex patterns, such as any of several words with different endings.

You can use ColdFusion variables and functions in regular expressions. The ColdFusion server evaluates the variables and functions before the regular expression is evaluated. For example, you can validate against a value that you generate dynamically from other input data or database values.

Note: The rules listed here are for JavaScript regular expressions, and apply to the regular expressions used only. These rules differ from the rules used by the ColdFusion functions REFind,REReplace,REFindNoCase, and REReplaceNoCase. For information on regular expressions used in ColdFusion functions, see Using Regular Expressions in Functions.