Javascript If Anything

Michael Zippo 04.11.2021

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An if‚Ä¶ else JavaScript statement evaluates whether a condition is true or false. If a condition is executed, the code inside the if block is executed. Otherwise, the contents of the else block are executed. Otherwise‚Ä¶ if the instructions allow you to evaluate more than one condition.

There will be times when you want to run different blocks of code, depending on certain factors.

Here is where conditional statements come in. Conditional statements are a crucial part of all programming languages. They execute blocks of code if a particular condition is met.

In this tutorial, we’ll see how to use if‚Ä¶ else statements in our code.

Updating conditional statements

As we have seen, conditional statements are an important part of any programming language. You will need to use a conditional statement to run the code if a particular condition is met. Here are some scenarios where using a conditional statement would be useful:

Checks whether a user’s password matches the password in the archive.
Checks if a user has an account listed under a certain email address.
Submit a form if all fields are completed.
View a list of vacation discounts if a user has terminated access.

The key to all of these examples is that they use the word if. If something happens, then something else should happen. Let’s explore how we can use this same logic in JavaScript.

JavaScript if statement

A JavaScript If statement evaluates whether a statement is true or false. An if statement will only be executed if the statement is true. If the statement is false, nothing happens.

If statements use the if keyword. After the if statement, you must specify a condition - or a set of conditions - in normal parentheses. The contents of an if and else statement appear in braces.

Here is the syntax for an if statement in JavaScript:

JavaScript example d ’if statement

Let’s use an example to show the if statement in action. We are building an eCommerce site and we need to make sure users are over 16 before making a purchase. Here is an example of how we can verify the age of users before allowing them to purchase an item from our store:

Our code returns the following:

Using the less than operator, we check if our user’s age is less than 16. Our user is 15, which means that userAge <; 16 is true. The code inside our if statement is executed.

What if our user’s age is 16 ? In this case, our code wouldn’t return anything because userAge <16 would be false. The code inside our if statement is ignored. Our program will continue to run.

The JavaScript if‚Ä¶ else statement
A JavaScript if‚Ä¶ else statement evaluates whether a condition is equal to true. If a condition is equal to false, the else statement is executed. Otherwise, the contents of the "if" statement are executed.

The syntax of the if‚Ä¶ Else statement is:

The else statement appears after any if conditions in a statement. Only an else statement can appear in an if statement.

To learn more about true and false JavaScript, read our guide on Boolean JavaScript .

si ‚Ä¶ Else JavaScript Example

Let’s use the same example from our discussion of the if statement where we check the age of a user. We’ll add an else statement to let a user know their purchase is in progress.

Our code returns the following:

We declare a JavaScript variable called "age" which keeps track of our user’s age. Since our user is over 16, the code ignores the if statement and executes the else clause. If the user’s age was 12, the code inside our else clause would not be executed.

Other declarations can be useful in a variety of contexts. For example, you can use an else statement to handle an error if it is displayed. Or you can use an else statement to check the contents of a form. You can display a message to users if they make a mistake or did not complete the form.

JavaScript else‚Ä¶ if statement
The JavaScript else‚Ä¶ if statement evaluates whether one of the multiple conditions is true. Each if‚Ä¶ else statement evaluates a new condition. If no condition is met, nothing happens.

Here is the syntax for using multiple else‚Ä¶ if statements:

Our program will execute all the statements in order, starting with condition one, and if none of the statements are true, the code will be all ’inside our else will be executed.
We have specified another‚Ä¶ if statement. You can use as many else‚Ä¶ if statements as you want with an if statement. In each statement, you must specify the code to execute if that particular condition is met. else‚Ä¶ if JavaScript Example Let’s use an example to illustrate an else & hellip; if conditional expression in action. Say you run a movie theater and want to offer customers different prices based on their age. Here are the prices you want to use: