Markdown editor with Showdown

Introduction

In this tutorial, you will create a simple in-browser Markdown editor using Showdown and some of its extensions. The purpose is to show how easy it is to include and configure Showdown in your project.

The fully working example you can see in Fiddle.

Step 1: Prepare project

Install node.js.
Install project package management tool

Showdown core library doesn't have any dependencies so the setup is pretty straightforward. However, you are strongly encouraged to use a package manager such as npm or yarn to manage project dependencies.

To install package management tool:
1. Create a directory called showdown-editor and recreate the following structure:
```
showdown-editor
├── css
│   └── style.css
├── js
│   └── script.js
└── index.html
```
2. Initialize package.json file by running the following interactive console command:
```
npm init -y
```
  This command creates package.json file in the root of the project folder, and populates the default content that you can change later if you wish.

Step 2: Install Showdown

Inside the showdown-editor directory, run the following command:

npm install showdown --save

This command will install showdown inside the node_modules directory and save showdown as a dependency in the package.json file.

Step 3: Update project files

Add the following content to the corresponding project files:

index.htmlstyle.cssscript.js

<!DOCTYPE HTML>
<html>
<head>
  <meta charset="UTF-8"/>
  <link rel="stylesheet" href="css/style.css"/>
</head>
<body>

  <textarea id="sourceTA" rows="10" cols="82">
Showdown Tutorial
=================

This is a showdown tutorial. 

Showdown supports a number of cool features, namely:

  - headers 
  - lists
  - and other stuff too

It is also possible to include code:

    var foo = 'bar';

    var baz = {
      markdown: 'is great',
      showdown: 'is awesome'
    }

Don't forget to check the [extensions wiki][1].

[1]: https://github.com/showdownjs/showdown/wiki/extensions
  </textarea>
  <hr/>
  <button id="runBtn" onClick="run()">Convert</button>
  <hr/>
  <div id="targetDiv"></div>

  <script src="node_modules/showdown/dist/showdown.min.js"></script>
  <script src="js/script.js"></script>
</body>
</html>

Please note how Showdown and the script file are included to the index.html via the script tag at the bottom of the file.

#sourceTA {
  display: block;
}
#targetDiv {
  border: 1px dashed #333333;
  width: 600px;
  height: 400px;
}

function run() {
  var text = document.getElementById('sourceTA').value,
  target = document.getElementById('targetDiv'),
  converter = new showdown.Converter(),
  html = converter.makeHtml(text);

  target.innerHTML = html;
}

The script.js file is simple: when the runBtn button is clicked, the script gets the text of the textarea, passes it through Showdown to convert the markdown text into HTML. The resulting HTML is then put inside the targetDiv, replacing the previous content.

Step 4: Check the result

Open your index.html file. You should see your editor with prefilled markdown text in the text area.
Click Convert button. You show see the text to be converted to HTML:

The fully working example you can see in Fiddle.

Conclusion

Congratulations! You have successfully created a simple Markdown editor!