How to Get the Mouse Position Relative to an Element in JavaScript

In this blog post, you will learn how to get the mouse position relative to an element in javascript. Let's dive into how it works!

Imagine you have a computer screen with a picture on it. When you move your mouse around, you can see an arrow on the screen that moves too.

Now suppose you want to know where the mouse arrow is inside the picture, not just on the whole screen. Maybe you want to know which part of the picture the arrow is pointing at so you can do something special there.

Get the mouse position relative to an element in JavaScript.#

To find out where the mouse arrow is inside the picture, you can use the following JavaScript code.

1. First, we use the querySelector() method to find the picture (div) element on the page. We can tell it which element we want based on its ID, which we designate with the # symbol. In this example, we're assuming the picture has an ID of picture.
2. Next, we use the addEventListener() method to tell the browser to watch for when the mouse moves over the picture element. When the mouse moves, we want to run some code to figure out where it is.
3. Inside that code, we use the event object that JavaScript creates whenever an event happens. This object has all kinds of information about the event, including where the mouse is. We access the mouse position with the clientX and clientY properties of the event object.
4. Finally, we use a little bit of math to figure out where the mouse is inside the picture element, not just on the whole screen. We subtract the picture's left and top offsets from the mouse position to get the relative position inside the picture. Then, we write the result on the picture element so we can see it.