WML designers must take this into account, although it can be hard to estimate the final binary size based on the plain text WML file. Battery life is also an issue. As a cell phone is required to send and receive more data, perform more processing and interpret more keyboard commands, battery life is drastically reduced. User interface One of the largest issues confronting designers is the user interface. It is very difficult to query the device and then adjust the display size and resolution on the fly.
Most cell phones use some variation requiring multiple key strokes per letter.
Typing in a long URL then becomes a challenge and a burden. Entering data is equally challenging. Scrolling through a long pick list not only requires patience but also a good memory. WAP offers a 'standard' keyboard mapping model, but not all WAP devices implement it the same. There is a wide variety of WAP devices currently available and the list grows every day.