How to center a button in Javascript

I am trying to center a button in Javascript so that it is horizontally centered in the page. Right now, my button is in a in my html file, so I don’t know how I can use CSS to center it since it’s in Javascript.

TLDR: In Javascript, if I hvae declared a button btn, what code should I write to center it horizontally?

I have searched all over the internet for a way to use Javascript to center a button to no avail. I hope you all can help me.

Thank you!

Answer

If I understand you correctly you want to center an already created button, it could work something like this:

<!--In only HTML-->
<button style="position: absolute; left: 50%; transform: translateX(-50%);">Click Me</button>

Another way to do it is to set an id to the button and then center it in a separate CSS file or in the <style> tag like so:

<!--HTML-->
<button id="myButton">Click Me</button>

/*  
  CSS 
  Remember to use a # before the name because it's an id you're trying to reach
*/
#myButton {
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
}

Or you could use JavaScript with the same HTML base

<!--HTML-->
<button id="myButton">Click Me</button>

And then in a separate JavaScript file or in the <script> tag

// Javascript
let myButton = document.querySelector("#myButton");  myButton.style.position = "absolute";
myButton.style.left = "50%";
myButton.style.transform = "translateX(-50%)";