Test for FontLoader.loading attribute On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". PASS document.fonts.checkFont('10px TestFont') is false PASS document.fonts.loading is false PASS document.fonts.loading is true PASS document.fonts.checkFont('10px TestFont') is true PASS document.fonts.loading is false PASS successfullyParsed is true TEST COMPLETE