How to make different texts in textarea display different colors_javascript skills

How to make different texts in textarea display different colors? If you control the style of textarea, all text will be the same color;

will not work if you put the text in a markup, because the markup will not be interpreted and is treated as text.

I found a method on the Internet:

I copied the code into txt and modified it into html format. The test works. The html is as follows:

Copy code The code is as follows:

< head>

< textarea id="test" name="topic" rows="10" cols="40">

Copy the above code into a txt, and then change the txt file It is an html file, for example, change it to a.html, open it with a browser, and click the "Submit" button, the running results are as follows: