Why is the focus event not working correctly on Iphone?

Question

css

Good afternoon, as we know, the $('.input').focus() events immediately point to the input where the courses should be set.
However, for example, the button is responsible for this event, I write my number (halfway) and press the cursor on the iphone put at the very beginning, ignoring that there are already some characters, it is extremely unpleasant, who has come across this?