XLS and HTML explained
The pre-2007 Excel format is a binary structure limited to 65,536 rows and 256 columns — limits modern datasets routinely exceed.
HTML is the markup language of the web, describing document structure — headings, paragraphs, lists, links — which browsers then render.
- Where XLS files come from
- Spreadsheets from Excel 2003 or earlier, and some legacy export systems.
- Where HTML is used
- Web pages, email templates and exports from documentation tools.