How does js implement a general regular validation form method (minimum code)

1. How to implement a general regular validation form with the least amount of code

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project, 1. Login has two input (verify mailbox, password 10 digits + letters)

   2.   input ()
   

both forms are displayed after input loses focus (correct or wrong message)

after input
Mar.01,2021
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-64f5-1b2bcd0-2bac1.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b2bcd0-2bac1.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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