This page helps developers find out which default fonts are available in their machine and how they render in the browser.
Just head to this page, choose a font size (or leave the default) and, if you want, an additional text.
You will see the list of fonts, each rendered with the font itself.
The page is clearly kept as simple as possible, with no obtrusive layout. Also, the fonts are loaded following this StackOverflow answer by Chris.