Open this HTML document in Safari: <!doctype html> <b>lorem ipsum</b> <script> console.log( getComputedStyle(document.querySelector('b')).getPropertyValue('font-weight') ) </script> Online version: https://output.jsbin.com/canijip/quiet In Chrome and Firefox, the console logs "700", but in Safari it logs "bold". The CSS Fonts specification [1] states that the computed value of the font-weight property is a number, so Safari should return "700" like the other browsers. [1]: https://drafts.csswg.org/css-fonts/#font-weight-prop
*** This bug has been marked as a duplicate of bug 214230 ***