Vue cannot be used under ie9, solution ~

I introduced
< script src= ". / js/vue.js" > < / script >
< script src= ". / js/vue-resource.min.js" > < / script >

and then ie11 simulates that 8 ie9 9 and 10 are all normal
but the real ie9 is not. The page is blank
error message ReferenceError: "index" is not defined

how to solve ~ ~ Thank you

Mar.04,2022
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-64f5-1e97dfc-168f.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1e97dfc-168f.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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