font-size-adjust should affect neigther computed line-height nor font-size. On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". PASS parseFloat(testStyle.getPropertyValue('font-size-adjust')) is within 0.0001 of 0.44 PASS referenceStyle.getPropertyValue('font-size-adjust') is "none" PASS testStyle.getPropertyValue('font-size') is "200px" PASS testStyle.getPropertyValue('line-height') is "200px" PASS containerStyle.getPropertyValue('line-height') is "200px" PASS successfullyParsed is true TEST COMPLETE xx