colourBrightness.js - Now without jQuery!

A lightweight and easy-to-use plugin that determines if the background colour of an element is light or dark.

How does it work?

Include the source file into your project and target the element with colourBrightness().

<script src="path/to/colourBrightness.js"></script>
<script>
  (function() {
    window.colourBrightness(document.querySelector('.lightbox'));
  });
</script>

It'll grab the background colour of that element and uses a small algorithm to determine the brightness of the colour and will add the class light if the colour is light and dark if the colour is dark.

From there, you can add what colour you'd like to display depending on the background in your CSS.

// Dark text
.light {
  color: #000;
}

// Light text
.dark {
  color: #fff;
}

Easy and don't need use jQuery!