Forms and Validation

In this tutorial, you'll learn how to make use of the validation helpers in dojox/validate with your Dijit-based form widgets to create customizable, validating forms—all on the client side.

  • Difficulty: Beginner
  • Dojo Version: 1.8

Getting Started

dojox/validate is a set of utility functions for common validation tasks, such as checking for a valid e-mail address, valid ZIP code (both the US and Canada), valid phone numbers, and more. It was designed for pure programmatic use—but also for use by various validation-based Dijits. In this tutorial, we'll look at what's available in dojox/validate, how to use the functionality directly, and how to use the functionality with widgets such as dijit/form/ValidationTextBox.

To get started, simply require the validation project, like so:

require(["dojox/validate"], function(validate) {
	
});

That's all there is to it to get the basic validation functionality, which includes the following methods:

validate.isInRange(test, options);
validate.isNumberFormat(test, options);
validate.isText(test, options);
validate.isValidLuhn(test);

Each one of these methods (except for isValidLuhn) can take an optional keyword arguments object to specify additional information about the check; for example, the isNumberFormat method takes an object that specifies the format to check against, like so:

var test = validate.isNumberFormat(someNum, { format: "(###) ###-####" });

It can also take an array of formats to check against, like so:

var test = validate.isNumberFormat(someNum, { 
	format: ["### ##", "###-##", "## ###"] 
});

Almost all of the validation methods take different options; check the documentation in the API documentation tools for more information about each of the methods.

Other Validation Methods

Obviously these 4 methods would not be enough for normal validation purposes; the dojox/validate codebase also includes a number of additional validation rules that can be included in your code by specifying the kind of validation you want to use. The additional validation resources are:

validate.creditCard
validate.isbn
validate.web

Unlike many of the module definitions in the Dojo Toolkit, require'ing these files does not create separate objects, but attaches new methods directly to dojox/validate. For instance, if your application needs validation rules for common web-related checks, you could do something like the following:

require(["dojox/validate/web"], function(validate) {
	validate.isEmailAddress(someAddress);
});

Finally, there are two more optional modules available that are North America-specific: dojox/validate/us and dojox/validate/ca. These modules each provide country-specific methods for checking for valid phone numbers, postal codes, social insurance/security numbers, and state/provinces.

Using dojox/validate with HTML-based forms

If your application uses straight-up HTML forms, dojox/validate has a module called check that allows you to define a validation profile (based on your form structure) that you can use to make sure all values in your form are valid. This profile is a JavaScript object/map, and is quite powerful—it can apply filters to field values, define a set of required values, define dependent values (for instance, if one field relies on another), constraints on values, and "confirm" fields (for instance, when requiring a password to be typed in twice).

To use the validation checker, you would have something like the following in your code:

// Since dojox/validate/check and dojox/validate/web just extend
// dojox/validate with new methods we don't need references to them
require([
	"dojox/validate",
	"dojox/validate/check",
	"dojox/validate/web"
], function(validate) {
	var profile = {
		trim: [ "field1", "field2" ],
		required: [ "field1", "pwd", "pwd2" ],
		constraints: {
			field1: myValidationFunction,
			field2: [validate.isEmailAddress, false, true]
		},
		confirm: {
			pwd2: "pwd"
		}
	}

	//	later on in the app, probably onsubmit on the form:
	var results = validate.check(document.getElementById, profile);
});

The return from dojox/validate/check is an object with several methods on it that you can then use to inspect any validation information on it. The methods are as follows:

isSuccessful(): Returns true if there were no invalid or missing fields, 
				else it returns false.
hasMissing():  Returns true if the results contain any missing fields.
getMissing():  Returns a list of required fields that have values missing.
isMissing(field):  Returns true if the field is required and the value is missing.
hasInvalid():  Returns true if the results contain fields with invalid data.
getInvalid():  Returns a list of fields that have invalid values.
isInvalid(field):  Returns true if the field has an invalid value.

The basic idea is that you perform the check, and then use the results to find out what parts of your form are valid and what are not before letting the browser process it. Take a look at the demo to see it in action!

View Demo

While dojox/validate/check is not well documented, there are good instructions on how the profile is constructed embedded in the comments of the source code.

Using dojox/validate with Dijit-based Forms

You can also use the functions in dojox/validate in conjunction with Dijit form elements— specifically Dijit's ValidationTextBox—as a way of validating your form elements. The key to this technique is ValidationTextBox's validator method. In your markup (or programmatically), all you need to do is set the validator of your ValidationTextBox to point to a reference of the function you want to use in dojox/validate, like so:

require(["dijit/form/ValidationTextBox", "dojox/validate/web"])

...and in your markup:

<input id="email" name="email"
	data-dojo-type="dijit/form/ValidationTextBox"
	data-dojo-props="validator:dojox.validate.isEmailAddress,
		invalidMessage:'This is not a valid email!'"
	/>

If you want your ValidationTextBox to use an optional keyword arguments object, just set the value of the constraints property:

<input id="range" name="range"
	data-dojo-type="dijit/form/ValidationTextBox"
	data-dojo-props="validator:dojox.validate.isInRange,
		constraints:{ min:10, max:100 },
		invalidMessage:'This is not within the range of 10 to 100!'"
	/>

Check it out!

View Demo

Conclusion

As you can see, dojox/validate provides some very useful utilities for your web-form based applications—both with regular HTML forms, and in conjunction with Dijit-based forms.



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