Alerts and Functions in JavaScript - Using Alerts, Prompts, and Confirm Boxes

JavaScript Alerts

In this tutorial, I will explain all there is to know about alerts and prompts in JavaScript. We will also learn about functions, including how and when they should be used.

Alert, Confirmation, and Prompt boxes are the most basic kinds of interactivity elements you can add to your JavaScript code.

Alert Boxes:

Alert boxes are to be used when you just want to pass on some information to the user. The user will be alerted with an alert box with whatever information you want to pass on and then he can click OK and go back to the page. The Alert box doesn’t return any values, unlike the Confirm and Prompt boxes.

The standard syntax for an alert box is

alert(“Hi, This is an alert box”);

Confirm Boxes:

Confirm boxes are generally used when you need confirmation from the user regarding some specific action. The confirmation box is displayed with text on it and the user can then click OK or Cancel. The return value is stored in a variable. If the user clicks OK, the value returned is true. If he clicks Cancel, the value returned is false.

Syntax for Confirm Boxes:

var returnvalue = confirm(“Hi, This is a confirmation box”);

Prompt Boxes:

While alert boxes are used to notify the user and confirm boxes are used to get a yes / no response, prompt boxes can be used to get text input from the user. The prompt box can be used to display information to the user and get a response. It has two buttons - OK and Cancel, and a textbox. If the user enters some text and presses OK, the input is stored in the return variable. If the user clicks Cancel, a null value is returned. You can also specify a default value in the textbox.

Basic Syntax for Prompt Boxes:

var returnvalue = prompt(“Hi, This is a Prompt box”, “This is the default value of the prompt box”);

Here is some code which will demonstrate all types of alert boxes.