Add HTML Elements to XUL Addons

By  on  

I've been working on a new addon at Mozilla which isn't anywhere near finished so I wont bother telling you what it's meant to do...because it could change at any moment.  Since this is my first real addon, it's been a struggle, but that's a good thing -- it means I'm learning a ton.  One problem I ran into was trying to get a checkbox (INPUT) element within the addon via JavaScript -- nothing was displaying.

After a bit of research and guesswork, I figured out what I was doing wrong -- I was using the wrong document method to create the element:

var input = document.createElementNS("", "input");

Using document.createElementNS with the proper namespace resulted in my checkbox displaying in all of its glory.  It's beautiful square, checked glory.  Firefox addons can be created in a number of ways so if you're looking to create your own and you aren't seeing HTML elements correctly, keep this solution in mind!

Recent Features

  • By
    CSS Filters

    CSS filter support recently landed within WebKit nightlies. CSS filters provide a method for modifying the rendering of a basic DOM element, image, or video. CSS filters allow for blurring, warping, and modifying the color intensity of elements. Let's have...

  • By
    7 Essential JavaScript Functions

    I remember the early days of JavaScript where you needed a simple function for just about everything because the browser vendors implemented features differently, and not just edge features, basic features, like addEventListener and attachEvent.  Times have changed but there are still a few functions each developer should...

Incredible Demos


  1. Reminded me of my initial days with JavaScript David! I also made the same namespace errors and then wondered for hours, what went wrong!

Wrap your code in <pre class="{language}"></pre> tags, link to a GitHub gist, JSFiddle fiddle, or CodePen pen to embed!