>Insmode(.F.) will join up the input number and its own number
>eg the value is 214, then i click and key in 5, it become 9214

No, it won't. However, Insmode(.T.) will give the result you have. But the best is to use a input mask, for instance 999999.

Sorry, is not 9214 but 5214.
the problem of input mask is key in 1 it gives 10 when you click other text box or button (without press enter key)