Some questions about document.body and document.documentElement

when there is a DTD declaration, document.body.scrollTop is 0st document. DocumentElement.scrollTop is the normal value.

The height of

document.documentElement.clientHeight is the height of the display area.

html is that the height of the root node containing body,body is stretched by the element, so why isn"t html? It"s an immutable value.

when you move the scroll bar, the part beyond the visual area is exactly equal to the scrolling distance, but the height of the documentElement is always the same. If you keep scrolling the scroll bar. The scroll bar moves an infinite distance. Must be larger than the size of the visible area. So why is documentElement equivalent to document.body?

Feb.15,2022
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-64f5-1b3e278-2c3e1.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b3e278-2c3e1.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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