It is critical to test across many browser and operating system combinations because the page can look different in each scenario. Another concern is the screen resolution and color depth. A page might look good at a resolution of 600 x 800, but parts of it might get cut off at 640 x 480. Different color depths should be used on the test machines also. Colors might vary unpredictably if a browser-safe palette is not used. As a QA, we should look for:
Color of links
Broken images
Low color contrast
Spacing in tables
Text wrapping issues
Margins
Alignment, formatting, and size of text
Alignment of controls such as radio buttons and check boxes
Switch Javascript off
Switch cookies off
Switch plug-ins off
Switch images off
Printing - Do not forget to test printing of your Web pages by printing on a variety of popular printers. Printing can be unpredictable, particularly with frames. Keep an eye on what is printed, the readability of content, and the speed of the print job.
Be sure to use clean machines when you start testing and make sure no plug-ins are installed. If the plug-ins are already installed,you might miss a defect that has a dependency on the plug-in. There should always be some test cases that involve using a browser as it is first installed,with no extra components.
Netscape Navigator requires a plug-in.Netscape users must be aware that the plug-in is required and should be given instructions on how to install it. (Anyway Netscape is a dying browser)
View in text browser (Incidentally the Opera browser has a built-in text-browser emulator)
