Xiaobai, what is the problem of using ajax to realize the error of undefined ajax in waterfall flow?

in order to achieve the effect of waterfall flow, the actual document can be found on localhost, but the following
clipboard.png

appears.

Xiaobai writes the ajax program directly in the index.js directory and still shows what went wrong with ajax not defined,. Ask for advice ~

Mar.18,2021

L14: XMLHttpRequest remove that s

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-64f5-1b3cf39-2bad1.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b3cf39-2bad1.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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