Why does Semantic HTML matter? Writing semantic HTML makes your code easier to understand, making the source code more readable for other developers. Screen readers and browsers can interpret Semantic HTML better, which makes it more accessible.
HTML defines six levels of headings. A heading element implies all the font changes, paragraph breaks before and after, and any white space necessary to render the heading. The heading elements are H1, H2, H3, H4, H5, and H6 with H1 being the highest (or most important) level and H6 the least.
The sup element represents a superscript. Superscript text appears half a character above the normal line, and is sometimes rendered in a smaller font. Superscript text can be used for footnotes, like ‘WWW’ The sub element represents a subscript. Subscript text appears half a character below the normal line, and is sometimes rendered in a smaller font. Subscript text can be used for chemical formulas, like H2O. These elements must be used only to mark up typographical conventions with specific meanings, not for typographical presentation for presentation’s sake.
When including an abbreviation or acronym, provide a full expansion of the term in plain text on first use, along with the to mark up the abbreviation. This informs the user what the abbreviation or acronym means.
WHY SHOULD WE AVOID USING TOO MANY INLINE STYLES: Inline styles increase the size of your pages, which ultimately makes your site slower. If you want each paragraph on your site to look the same, you can do it once in the stylesheet, costing you maybe 10 lines of code. However, if you use inline styles, you’ll have to include them in every paragraph.