When using www.gmail.com in Safari, after a few minutes of typing, screen will "flash" and go back to Home screen. Data in Gmail is lost except for drafts saved. This happend in ver 4.n and now in 5.x for iPad 1
OK - when Safari returns to the Home screen, it's because it's run out of system memory (RAM). To free up RAM, switch the iPad completely off by pressing and holding the Power switch until the slider control appears.
Switching the iPad on and off allows the operating system to carry out a number of housekeeping tasks, including freeing up system memory.