These are the three most common cases that I find for needing raw HTML:
1. Adding classes to elements, for styling; admittedly this may be inapplicable to some visions of a document web, if you can’t write stylesheets.
2. Images. If you’re dealing with known images, you should always set the width and height attributes on the <img> tag, so that the page need not reflow as the image loads. Markdown’s image syntax () doesn’t cover that. (Perhaps an app could load the image and fill out the width and height as part of its Markdown-to-HTML conversion, but I haven’t encountered any that do this.)
3. Tables. CommonMark doesn’t include tables, and even dialects that do support tables are consistently insufficient so that I have to write HTML. For example: I often want the first column to be a heading; but I don’t think any Markdown table syntaxes allow you to get <th> instead of <td> for the first cell of each row.
1. Adding classes to elements, for styling; admittedly this may be inapplicable to some visions of a document web, if you can’t write stylesheets.
2. Images. If you’re dealing with known images, you should always set the width and height attributes on the <img> tag, so that the page need not reflow as the image loads. Markdown’s image syntax () doesn’t cover that. (Perhaps an app could load the image and fill out the width and height as part of its Markdown-to-HTML conversion, but I haven’t encountered any that do this.)
3. Tables. CommonMark doesn’t include tables, and even dialects that do support tables are consistently insufficient so that I have to write HTML. For example: I often want the first column to be a heading; but I don’t think any Markdown table syntaxes allow you to get <th> instead of <td> for the first cell of each row.