Test canvas createImageData() On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". PASS ctx.createImageData(null) threw exception Error: NOT_SUPPORTED_ERR: DOM Exception 9. PASS imageData.width is 100 PASS imageData.height is 50 PASS imageData.data[32] is 255 PASS sameSizeImageData.width is 100 PASS sameSizeImageData.height is 50 PASS sameSizeImageData.data[32] is 0 PASS imgdata1.data.length is 800 PASS imgdata1.data.length is imgdata2.data.length PASS imgdata2.data.length is imgdata3.data.length PASS imgdata3.data.length is imgdata4.data.length PASS successfullyParsed is true TEST COMPLETE