In the world of documentation, alert boxes play a crucial role in drawing attention to important pieces of information. In Markdown, these boxes, also often referred to as warning boxes, are not native features. However, there are ways we can implement this into our Markdown syntax with certain flavors of Markdown.

In this tutorial, we will explore two methods of adding a warning box or an alert to your Markdown content. First, using the blockquote syntax with specific keywords, and second, using HTML within your Markdown.

Method 1: Using Blockquotes

The blockquote method is the easiest way to create an alert or warning box in your markdown. It works well with Github-flavored and other similar flavors of Markdown.

In Markdown, a blockquote is created with a ‘>’ symbol followed by a space. Anything following this symbol on the same line will be included in the blockquote.

> **WARNING**: This is a warning message! Be careful!

When rendered, the output will be:

WARNING: This is a warning message! Be careful!

Although it does not look like the conventional warning box, it stands out from the main body of the document, serving the basic purpose of a warning box.

On some platforms and with some styles, it will be displayed with a vertical line or a different background color.

However, there’s no guarantee that this will look like a traditional alert box on every platform because the presentation of blockquotes depends on the platform’s CSS markdown rendering. This is one reason you might prefer using HTML instead (explained below).

You can familiarize yourself more with how blockquotes work in markdown using this detailed guide on our blog here.

Method 2: Using HTML

Markdown allows for HTML to be used within its content as markdown translators simply ignore HTML tags. This allows for more customizable rendered output.

Here is an example of adding a warning box using HTML:

<div class="alert">
  <strong>Warning!</strong> This is a warning alert.
</div>

The output will be highly dependent on your CSS, but if you have an “alert” class with certain styles it could appear as a traditional warning or alert box.

An important thing to remember is that when using HTML in markdown, the inner text must use HTML tags as markdown syntax will not be recognized.

HTML provides more customization and the possibility of creating traditional alert boxes. However, not all Markdown processors preserve the HTML tags. Therefore, it’s important to understand the markdown specifications of your specific environment.

Note: If you’re working with React, check out our tutorial on Rendering Markdown in React, which will guide you on how to safely render markdown content that includes HTML.

Conclusion

While Markdown does not natively support warning or alert boxes, we can still create similar structures using blockquotes or HTML. These methods aren’t foolproof but serve as a suitable way to highlight important information. To ensure your Markdown renders as expected across different platforms, always check the specifics of your Markdown processor or environment.