Summarize this article in one sentence.
Word has the built-in ability to convert documents into HTML format. The result is usually bulkier than a standard HTML page, and may contain formatting that does not work on all browsers. For example it does not use the standard HTML list tags for lists, instead it relies on heavy use of CSS to style documents.  It will, however, still contain formatting information that can be used to convert it back into an ordinary Word document for later editing. Go to the File menu and select "Save As." On some versions of Word, such as Word 2012, the Save As option is found under the "Home" button instead. Once you select "Save As," you'll be taken to screen with a drop-down menu, listing the types of file formats you can save as. Select "Web Page" to save it as an HTML file. If you cannot find this option, edit the file name by adding your own .htm or .html extension, then surrounding the file name with quotation marks: "ExampleFile.html". On some versions of Word, you can save it as a "slimmer" HTML file that looks the same, but will load faster as a web page. If you do not plan to convert the document back to a Word file again later, select "Web Page, Filtered" instead. If this options is not available in your software, save it as a normal "Web Page," then use AlgoTech's Mess Cleaner tool online to convert to a slimmer HTML file.

Summary:
Open the document in Microsoft Word or OpenOffice. Select "Save As." Choose "Web Page." Save it as "Web Page, Filtered" if available.