What is the relationship between the V8 engine and the javascript engine and the javascriptCore engine

I am idle and bored to look at the knowledge of browsers. These three engines have been mentioned, which have been confused all the time.
can these three engines be understood as that the V8 engine is an upgraded version of both the javascript engine and the javascriptCore engine? Is it better than javascript engine and javascriptCore engine in terms of performance and efficiency?
then what is the relationship between javascript engine and javascriptCore engine

Webkit browser-kernel javascript

Mar.05,2021

javascriptCore and v8 are both javascript engines. Refer to javascript-engine

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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-64f5-1e9cbd2-6906f.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1e9cbd2-6906f.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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