A full blown opera is nothing more than music and script with detailed instructions to the players and cast to show off their talents. To get a web page to your computer, you have to use a browser software such as Netscape, Mosaic, or the built-in browsers of AOL, Compuserve, Prodigy, etc. Just like a traveling opera with a piano and four singers standing on a bare stage. Basically, an HTML document is a text file with codes embedded that get interpreted by the browser software on your computer, and unfolded in a special way on your screen. A basic melody with harmonies, grace notes, and dynamic markings to add interest.
Interpretation is flexible.
You can leave out the grace notes if you don't have the technique to handle them. Web pages are designed to provide access by a wide range of computers running a wide variety of software. If a browser can't interpret the codes, it politely ignores them, on purpose. A sheet of music, especially to a non-musician, looks like gibberish. Our traveling opera company can perform Madame Butterfly with a piano and a few singers, and it will still sound like the opera, although without the full glory of the orchestra, stage, costumes, and dancing.