Too Long; Didn't Read
Use HTTPS for embedded resources where possible. Use HTML5 (HTML syntax) for all HTML documents: <!DOCTYPE html>. Use HTTPS (https:) for images and other media files, style sheets, and scripts, unless the respective files are not available over HTTPS. The contents of a page title is very important for search engine optimization (SEO) Use the lang attribute inside the <html> tag, to declare the language of the Web page. This is meant to assist search engines and browsers.