Upload the PHP or HTML file to your site, then visit it and choose your font selection using comma-separated values. If no fonts are given, it defaults to Georgia.
http://example.com/responsive-type.php?font=Georgia,Helvetica,Times New Roman
http://example.com/responsive-type.html?font=Georgia,Helvetica,Times New Roman
You can also add in your Typekit ID if you want to include web fonts:
http://example.com/responsive-type.php?typekit=nqy2rqt&font=Georgia,Helvetica,chaparral-pro
Or even add in your Google Web Fonts:
http://example.com/responsive-type.php?google=Prosto+One&font=Georgia,Helvetica,Prosto One
If you really can't decide what font to use, you can even include both font libraries:
http://example.com/responsive-type.php?typekit=nqy2rqt&google=Prosto+One&font=Georgia,chaparral-pro,Prosto One
Some fonts might look very similar, so how do you know if it's been included in your page? What happens if you've made a typo in the URL? I've added a script that detects what font is supposed to be there and compares it with the base font. This script is from lalit.lab, I did none of the hard work.
If the font is available, you get a green square next to the font name. If not, you get a red square. You might not want the overhead of javascript, so you can exclude it from the page using the 'js=no' parameter (PHP version).
http://example.com/responsive-type.php?font=Georgia,Helvetica&js=no
The font availability script works for the JavaScript version, but not for web fonts. I'll try and fix this is future releases.
This version is in beta and still needs some testing and alteration, but use away and provide some feedback or modifications.
Forked from the original idea by @Malarkey. PHP feedback, ideas and support to @thefella.