is-invalid class for a text box not works

I want the text box to be red color bordered when there is no value inside the text box <input type="tel" #phone="ngModel" [class.is-invalid]="phone.invalid" class="form-control" name="phone" [(ngModel)]="userModel.phone">

I want the text box to be red color bordered when there is no value inside the text box <input type="tel" #phone="ngModel" [class.is-invalid]="phone.invalid" class="form-control" name="phone" [(ngModel)]="userModel.phone">

How to Create an Animated Navbar with Html, CSS and JavaScript

How to Create an Animated Navbar with Html, CSS and JavaScript

In this Html, CSS and JavaScript tutorial you will build an animated navbar with Html, CSS and JavaScript. Have you every wanted to create an awesome animated navbar with JavaScript? We will be looking at making a navbar with Html and CSS and then using the intersection observer in JavaScript to help us create this effect.

Javascript Animated Navbar Tutorial

Have you every wanted to create an awesome animated navbar with javascript? no? oh well...this is akward.

All jokes aside we will be looking at making a navbar with html and css and then using the intersection observer in javascript to help us create this effect.

TIP Calculator using HTML, CSS & Javascript

TIP Calculator using HTML, CSS & Javascript

We take a deep dive into how to code a tip calculator using HTML, CSS & Javascript. This tutorial can be considered as a beginner tutorial. We look into form inputs, styling form inputs in CSS & HTML while using Javascript to create the interactivity needed to calculate tips.

We take a deep dive into how to code a tip calculator using HTML, CSS & Javascript. This tutorial can be considered as a beginner tutorial. We look into form inputs, styling form inputs in CSS & HTML while using Javascript to create the interactivity needed to calculate tips.

How to Create Attendance Register in JavaScript, CSS, and HTML

How to Create Attendance Register in JavaScript, CSS, and HTML

How to Create Attendance Register in JavaScript, CSS, and HTML. The tutorial includes the use of JavaScript functions, image, Table, Option, input, and other components.

How to Create Attendance Register in JavaScript, CSS, and HTML. The tutorial includes the use of JavaScript functions, image, Table, Option, input, and other components.