Android version of Chrome browser cannot be implemented through preventDefault to prohibit the entry of specific characters in < input >?

imagine that < input > listens to the keydown event, determines the keyCode of the event parameter object, and then calls preventDefault () to block the input of illegal characters.

sample code:

   

the version of the mobile operating system is Android 7.1.1.

Why is the output in the Chrome browser inconsistent with Firefox, and why can"t input be blocked through preventDefault () ?

Dec.10,2021
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1beaec0-3127e.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1beaec0-3127e.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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