help!

Question

how to make sure user only put a number instead of letter in a prompt box .. example if he/she put a letter in a prompt box and click "ok", there's an alert box would display "error" or something like that.

Answer 1

Check every character of the string (using a for loop etc,). If one non number occurs, alert an error.

Answer 2

in android we can say that wich parameter we need just by a click on "textnumber"
In other situation we can separate it to characters and use "switch".
then check if it is a number from 0-9