H5 how can the mobile end cut out the special characters after entering them, or cannot enter the special characters at all?

this is my code can be perfectly implemented on the PC side, but when I enter a special character for the first time on the mobile side, I will not cut any character for the second time. Or is there any other better way to ask for advice!

Mar.09,2021

there are no keyboard events on mobile, so you can change it to @ touchstart

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