AngularJS provides great support for implemeting validations in Forms.
Validation is performed by States properties and Validators directives.
There are four States in AngularJS Forms.
- $invalid : This state describes that form is in invalid state.
- $valid : This state describes that form is in valid state.
- $dirty :This state describes that form is in dirty state means any one input control value has changed by user.
There are main four AngularJS Validators directives.
- ng-required : Set input control required and set the 'required' attribute of $error if input control is empty.
- ng-minlength : Set minimum length of input field and set the 'minlength' attribute of $error to true if input control does not satisfy the ng-minlength validation.
- ng-maxlength : Set maximum length of input field and set the 'maxlength' attribute of $error to true if input control does not satisfy the ng-maxlength validation.
- ng-pattern : Match the reqular expression and set the 'pattern' attribute of $error to true if input control does not satisfy the ng-pattern validation.
In addition we used three additional directives:
- ng-model : Bind input controls to AngularJS controller objects.
- ng-disabled : Disabled the associated element while condition is satisfied.
- ng-show : Show the associated element while condition is satisfied else hide the element.
AngularJS Form Validation Example
- Line 9 defines an input control which has ng-model, ng-required, ng-minlength, ng-maxlength directives.
- Line 10,13,16 defines a ng-show directives which only visible when its associated bind property is set to true.
- Line 11, 14, 17 shows error messages which only visible when ng-show directive is set to true.
- Line 21 shows an example of ng-pattern directive which validate the input control for valid email.
- LIne 22, 25 span will only be visible when bind properties is set to true.
- Line 30 defines an input submit button with ng-disabled directive which disable the submit button until the form is in valid state.
- Line 36 to 46 defines an angular app and controller which show the user information in console when user submit the form.