The purpose of a form validation script is to return a boolean value ('s to reference form fields, but that can lead to namespace conflicts and why make things more complicated than necessary.
When the form is submitted - either by hitting Enter or clicking on the Submit button - the (the 'value' of the field called 'input' belonging to the form). In a real-life situation you will most likely have more fields to check, and more complicated conditions, but the principle remains the same.
Step 5: Run the application, the page will displayed with disabled submit button.
Try to add value in the First Name and remove it, the validation will be executed and an Error message will be displayed as shown here: Note: With Angular 1.3 and ng-touched, as soon as the control has blurred, you can now set a style on it, regardless of whether the value in the control was actually edited or not.
attribute that you can supply a regular expression to constrain what can be typed in.
However, not all browser support HTML5 elements and attributes and it may not be 100% for you.
More Info: You could use Java Script to prevent it from happening and it isn't foolproof either as Java Script can be turned off in the browser.
Your best bet would be to utilize a server-side scripting language (i.e.Here, we are giving our Java Script codes for validating Login form.In our example, we have a login form with two input fields i.e.ng-class is the Angular directive used to apply class on the elements based upon the evaluated expression.The expression ", checks the validation on first Name using $invalid and $dirty. Since we have several validation checks on element, we need to display corresponding error messages e.g.It can prevent people from leaving fields blank, from entering too little or too much or from using invalid characters.