How to Code an Alert with a Variable Using JavaScript

Simple steps to notify users with a variable from your JavaScript code

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Last Updated: March 7, 2025

• Setting Up the Variable
|
• Making the Alert
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• Q&A
|
• Tips

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Alerts with variables are among the most useful things in javascript coding. You can use them to refer to someone by their name, to make a mini MadLibs game, or even for showing quiz results. This article will show you how to make a variable-based alert.

Steps

Part 1

Part 1 of 2:

Setting Up the Variable

1. 
   1
   Write the first line of code. Type "var username = prompt ('What is your name?');". Replace "username" with whatever you want to call your variable. Replace "What is your name?" with whatever you want to ask for.
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Part 2

Part 2 of 2:

Making the Alert

1. 
   1
   Write the next line of code. Type "alert ("Hey, " + name + "!");". This line of code will add the variable "name" to the word "Hey, "(with the space at the end), and then add "!" to end the sentence (not required). For example, if the user inputs "Trevor" as the value of the variable "name", the alert will say "Heya, Trevor!". You can use any message you want, though. If your variable is "favoriteColor" and "Blue" is the value, for instance, you can have the alert say "Blue is a very nice color! "
2. 
   2
   Add in more variables if you want. Try to make a one or two sentence biography.
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Community Q&A

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• Question

  How to make a prompt in a JavaScript?

  

  Community Answer

  Use "prompt(text);". It opens a window with a text field and shows the text that is inside the (). For instance, if you have a variable called foo and you want to set its value to something the users inputs, such as their username, you might do this: foo = prompt("Enter your username:") or, if you haven't defined foo already, var foo = prompt("Enter your username:").

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  What software is this?

  

  Arrogance

  Top Answerer

  The text editor depicted in the images is Notepad++.

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Tips

• All function calls and declarations should end with semicolons! For instance, don't write "alert(username)", instead write "alert(username);"! This tells the computer where to stop reading something and start actually doing it.
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• Try writing some lines of code before the alert code to repeat the prompt if the response is null.
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