css:

link

  • 1, link in the style, is parsed by the CSS parser, and is synchronous parsing;
  • 2. The CSS parser blocks the rendering of the page (it can be used to avoid splash screens);
  • Block the execution of subsequent JS statements.
  • 4. Don’t block DOM parsing
  • Block browser rendering

style

  • 1. The style in the style tag is parsed by the HTML parser.
  • 2. Browsers load resources asynchronously.
  • 3, page style tag write internal style is asynchronous parsing;
  • 4. Don’t block DOM parsing
  • 5. Do not block browser rendering

js:

  • 1. Block the execution of subsequent JS statements;
  • Block DOM parsing
  • Block browser rendering

Neither SCC nor JS blocks browser loading resources