When it comes to a certain div, then use jquery to do the action?

I don"t know what kind of technique this is
https://tinder.com/
like this
can run out of the west after going to a certain div area
how can this be done?

Mar.10,2021

this is a piece of code originally written

  ScrollMagic  

you can keep the reference. Of course, I still recommend the method of Ls.

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-64f5-1e5b960-43bef.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1e5b960-43bef.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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