问题
When was full support for numeric font-weight added to each browser? Specifically: IE, FireFox, Chrome, Safari, iOS Safari, Android Browser.
I know all browsers support bold and normal, but I've been unable to find a up-to-date list of browsers that fully support numeric values for the CSS font-weight property. The only info I found was Font-weight is still broken. It shows most browsers at the time failing to render numeric weights correctly but it's from 2009 before IE8 was even released.
Example:
<link href='http://fonts.googleapis.com/css?family=Roboto:300,400,700' rel='stylesheet' type='text/css'>
<style>
body { font-family: 'Roboto', sans-serif; }
.light { font-weight:300 }
.normal { font-weight:400 }
.bold { font-weight:700 }
</style>
回答1:
AFAIK, the numeric values for font-weight are there since font-weight was supported on each browser... the thing is that all nuances of the weight (all that numeric-scale spectre), depends on the font itself (from the user's machine, or if you've added via @font-face), if the font doesn't have a "semibold", 500 won't do anything.
You can take a look to the specification, there's an explanation of how browsers behave when the weight is not present at the font: http://www.w3.org/TR/CSS21/fonts.html#font-boldness
Hope this can help
来源：https://stackoverflow.com/questions/28589841/browser-support-for-numeric-font-weight