What is Blue Light? How to Implement Dark Mode on Your Website

These days, digital devices are a part of everyday life. Most people work on a computer for several hours and view their phones multiple times a day. Plus, traditional books have been replaced with tablets that many people used before bed.

According to studies, 80% of American adults use electronics for more than two hours a day. While technology is useful, constantly looking at digital screens can create issues like eye strain and it exposes the eyes to blue light.

If you’re asking yourself “What is blue light?”, we’ll explain it to you in the information below. Just keep reading.

What Is Blue Light?

Blue light is a pigment that’s in the visible light spectrum category that can be seen by the human eye. It has a wavelength of nearly 380 nm and 500nm, which makes it one of the shortest, high-energy wavelengths.

Blue light is all around. It’s outside, and it illuminates when the sun travels through the atmosphere. It also comes through sources like computers, TVs, smartphones, tablets, fluorescent lights, and LED lighting.

The Difference Between Natural and Artificial Blue Light

When you’re outdoors, the sun travels through the environment. The blue light wavelengths collide with the air molecules causing the blue light to spread all over the atmosphere.

This occurrence is what makes the sky look blue. In its natural state, the body uses blue light to regulate sleep and wake cycles. This is referred to as the circadian rhythm.

Additionally, blue light improves alertness, elevates mood, increases reaction time, and boosts overall well-being. On the other hand, artificial blue light from electronic devices is a bit different.

Since blue light waves are short, they flicker easier. The flickering creates a glare that minimizes visual contrast and hinders sharpness and clarity.

It also is the primary cause of eyestrain, mental and physical tiredness, and headaches. The human body is not equipped with the proper amount of protection against natural light rays, and it’s especially not artificial blue light.

Extensive exposure to it could cause retinal damage and other vision problems.

To combat these issues, many people choose to wear blue light computer glasses as they work. Also, most websites have started to implement dark mode as an option for users.

If you want to learn how to use the Google Chrome dark mode, click the highlighted link.

What Is Dark Mode?

Dark mode is a dim-light user interface that uses a dark color like grey or black as the background color. It’s a default reversal that web designers have used for many years.

However, nowadays with so many people viewing digital devices more often, the dark theme helps to reduce eye strain. It’s especially good for applying before bed or in low-light environments.

The less eye strain a person has, the fewer symptoms they experience, which allows them to work more efficiently.

Ways to Implement Dark Mode

There are a handful of methods that you can use to add dark mode to your website. Check them out below:

Pure CSS

Pure CSS has a color scheme media query that can be used to recognize a user’s color scheme preference. It usually come in three values which are light, dark, and no preference.

To use this method, you can put the dark theme styles in the media query. However, if a web user has turned on dark mode from their system settings, dark mode styles will appear by default.


JavaScript is a great way to detect the site user’s color scheme preference. The negative aspect of using JavaScript is that it’ll probably give a sudden clash of light theme as it’s executed after the CSS.

OS Setting Override

Web users also have the option to override their system to use a particular preference for a site. Some people like dark mode for their operating system, but not on certain websites.

That’s why it’s good to provide an option to manually override dark mode regardless of the system settings.

Browser Support

The good news is, many browsers like Chrome, Firefox, and Safari support the prefers- color- scheme media query.

That’s great seeing as though many web visitors can apply the dark mode preference straight from the web browser, rather than individual websites.

How to Store a Website Users Preference

One of the main aspects of switching to dark mode is recognizing and saving the user’s preference so that it shows up through all of the web pages. It’s also important that it continues to show up on web visits following let’s switch.

You can do this by saving the user’s preference to the local storage when the theme is toggled. Here are a couple of options.

Local Storage: By using a script that saves the chosen theme to the local storage when the toggle occurs, it reloads the script and retrieves the choice from the local storage and applies it. Again, since JavaScript usually runs after CSS, there may be a Flash of Incorrect Theme (FOIT).

Cookies with PHP: Using a side script by PHP allows you to create a cookie from Javascript and save it there. That’s an alternative option, rather than saving the users theme preference in local storage.

However, this is only ideal if you’re currently using a server-side language.

Protect Your Website Viewers from Blue Light

What is blue light? Well, It’s definitely something you should protect your website visitors from. Everyone doesn’t use blue light blockers, so give them a little help. After reading this information, it’s easy to understand why dark mode is essential for your site.

If this article was useful, feel free to browse the rest of our blog. We cover all things tech and share helpful tips for web designers and developers. Check us out.

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