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Alerts In Javascript

In this article, we will discuss alerts in JavaScript.

Purpose

Alerts in JavaScript are used to provide information to the user or to get information from the user.

Types Of Alerts

There are three types of alerts in JavaScript: -

Alert box
Confirm box
Prompt box

Alert Box

This alert is used to give some information to the client like showing an error message if something is wrongly entered by the user, displaying a confirmation message, and so on.

Example

alert("Hi,this message is for information purpose.");

Try It

Output

Picture showing the alert box in JavaScript

Confirm Box

This alert is mainly used if it is required to get yes-no confirmation from the user. For example, if the user is saving the value in the database, then it is always good to confirm with the user if he wants to save the value.

Confirm box returns a Boolean value depending upon the option selected by the user. If the user selects Yes then returns true else false.

Example

if(confirm("Are you sure you want to save your personal information?") == true) {
        // Do Something
}
else{
        // Do Something else
}

Try It

Output

Picture showing the confirm box in JavaScript

Prompt Box

A prompt box is required in the scenario in which you want some input from the user. Let us consider a system that requires the system to enter the age of the person and based on which it gives information on whether the user is eligible for the vote or not.

Example

var age = prompt("Please enter your age", "18");
 if (parseInt(age) >= 18) {
  alert("You are eligible to vote");
 } else {
  alert("Sorry,you can't vote");
 }

Try It

Output

Picture showing the prompt box in JavaScript

If the user clicks ok then value 18 is assigned in variable age else null. So be careful in handling the value when you are using the prompt box.

Posted By -	Karan Gupta

Posted On -	Tuesday, March 22, 2011

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