Specify fallback font sizes in CSS?

Question

Is there any way to specify different font sizes for fallback fonts in CSS? I want to do something like this (which obviously does not work):

div {
    font-family: "Arial Narrow", Arial, Helvetica, sans-serif;
    font-size: 20px, 18px, 18px, 18px;
}

The idea being that Arial Narrow would display at 20px if the user has it installed; if not, the browser would fall back to Arial at 18px, then Helvetica at 18px, etc.

Or, could I use JS to achieve a similar effect?

Answer 1

I understand what you want, but I think the answer to your question is "No, this can't be done in CSS", at least not in CSS2 afaik.

Hoping someone can prove me wrong, 'cause i want this too :D

I suppose JS can accomplish this, at least up to some point. Not sure if there is a "is this font installed?" method in JS, but you may be able to make some educated guesses based on OS and such. Got no experience there sorry.

Edit: some quick googling does provide a few clever JS tricks, though I haven't tried them yet. E.g. http://remysharp.com/2008/07/08/how-to-detect-if-a-font-is-installed-only-using-javascript/

Another edit, after some more searching: I was triggered by the "someone should propose it" :D. It seems CSS3 spec has the "font-size-adjust", which may be of use here. However, support in browsers other than Firefox may not be optimal at the time I write this. Here's the W3 word on that property: http://www.w3.org/TR/WD-font/#font-size-adjust

Answer 2

I had a related problem using CSS3 fonts, which obviously don't work in IE6-8. The fallback font (Arial) is much bigger than the default font. Got round it in a similar way to mVChr but by detecting the browser. Not pretty really, but the joys of having to support IE. Code (with jQuery):

<script>
    $(document).ready(function() {
        //change font sizes in IE6-8 because they display Arial not Dincon
        if(navigator.userAgent.indexOf('MSIE 6') > -1 
         || navigator.userAgent.indexOf('MSIE 7') > -1 
         || navigator.userAgent.indexOf('MSIE 8') > -1) {
            $('.offending-class').css('font-size', '11px');
        }
    });
</script>