Web FontFonts are high quality, screen-optimized fonts designed specifically for web use. FontFonter uses custom CSS and other techniques to temporarily replace a site’s font styles with Web FontFonts, making it a great tool for web designers to quickly see how their site will appear using different font combinations with doing any coding.
FontFonter also offers a handy browser bookmrarklet that works in Safari, Chrome and Firefox which brings up a small floating panel to allow you to select serif and sans-serif fonts to apply the site you’re currently viewing.