jQuery.validator.addMethod()

Add a custom validation method. It must consist of a name (must be a legal javascript identifier), a javascript based function and a default string message.

Description

For simple one-off validation, you can use the bundled pattern method (in additional methods, source in src/additional/pattern.js) to validate a field against a regular expression. In general, it is a good idea to encapsulate those regular expressions inside their own method. If you need lots of slightly different expressions, try to extract a common parameter. See also a library of regular expressions.

Usage

`jQuery.validator.addMethod( name, method [, message ] )`

name (String)

The name of the method used to identify it and referencing it; this must be a valid JavaScript identifier

method (Function)

The actual method implementation, returning true if an element is valid. First argument: Current value. Second argument: Validated element. Third argument: Parameters.

value (String) - the current value of the validated element
element (Element) - the element to be validated
params (Object) - parameters specified for the method, e.g. for min: 5, the parameter is 5, for range: [1, 5] it’s [1, 5]

message (String) (optional)

The default message to display for this method. Can be a function created by ‘‘jQuery.validator.format(value)’’. When undefined, an existing message is used (handy for localization), otherwise the field-specific messages have to be defined.

Examples

Example 1

Add a validation method that checks if a value starts with a certain domain.

jQuery.validator.addMethod("domain", function(value, element) {
  return this.optional(element) || /^http:\/\/mycorporatedomain.com/.test(value);
}, "Please specify the correct domain for your documents");

Example 2

Adds a validation method that checks if a given value equals the addition of the two parameters.

jQuery.validator.addMethod("math", function(value, element, params) {
  return this.optional(element) || value == params[0] + params[1];
}, jQuery.validator.format("Please enter the correct value for {0} + {1}"));

Example 3

Adds a custom email validation method that is less strict than the one built-in.

jQuery.validator.addMethod("laxEmail", function(value, element) {
  // allow any non-whitespace characters as the host part
  return this.optional( element ) || /^[a-zA-Z0-9.!#$%&'*+\/=?^_`{|}~-]+@(?:\S{1,63})$/.test( value );
}, 'Please enter a valid email address.');