How To Write Conditional Statements in JavaScript

Introduction

In programming, there will be many occasions in which you will want different blocks of code to run depending on user input or other factors.

As an example, you might want a form to submit if each field is filled out properly, but you might want to prevent that form from submitting if some required fields are missing. In order to achieve tasks like these we have conditional statements, which are an integral part of all programming languages.

Conditional statements execute a specific action based on the results of an outcome of true or false.

A few examples of JavaScript conditional statements you might see include:

• Check the location of a user and display the correct language based on country
• Send a form on submit, or display warnings next to missing required fields
• Open a dropdown on a click event, or close a dropdown if it is already open
• Display an alcohol purveyor’s website if the user is over the legal drinking age
• Display the booking form for a hotel but not if the hotel is booked

Conditional statements are part of the logic, decision making, or flow control of a computer program. You can compare a conditional statement to a “Choose Your Own Adventure” book, or a flowchart.

In this tutorial, we will go over conditional statements, including the if, else, and else if keywords. We will also cover the ternary operator.