Gecko has had off-the-main thread HTML parsing since Firefox 4. Docs: https://developer.mozilla.org/en-US/docs/Mozilla/Gecko/HTML_parser_threading https://devel

Gecko has had off-the-main thread HTML parsing since Firefox 4. Docs: https://developer.mozilla.org/en-US/docs/Mozilla/Gecko/HTML_parser_threading https://developer.mozilla.org/en-US/docs/Mozilla/Gecko/HTML_... WebKit/Blink put fewer parts of the HTML parser off the main thread, so negative results should not be taken to apply to more comprehensive approaches.