How to Call Functions in JavaScript

If you’re just getting started with JavaScript, you may be wondering how to call functions. In this article, we’ll show you how to do just that!

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In JavaScript, there are several ways to call functions. The most common way is to use the function’s name followed by parentheses, like this:


You can also use the built-in JavaScript eval() function to call a function by name:


Another way to call a function is to first assign the function to a variable, and then call the variable as a function:

var fn = function() { /* do something */ }; fn();

Calling Functions

In JavaScript, there are several ways to call functions. The most common way is to simply call the function by its name, like this: functionName();. You can also call a function using its named parameters, like this: functionName(param1, param2).

Calling a Function by Reference

You can call a function by reference using the function’s name followed by parentheses. For example, you could call the myFunction function defined in the above example as follows:


Calling a Function by Value

In order to call a function by value, you simply need to pass the value of the variable into the function as an argument. For example, if you have a variable named “x” that contains the number 5, you can call the square function by passing 5 into it like this:


This would return 25 since 5 squared is 25.


We’ve seen how to call functions in JavaScript, and how to pass arguments to them. We’ve also seen how to return values from functions.

Calling functions is a fundamental part of using JavaScript, and understanding how it works is essential for being able to write code that is easy to read and debug.

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