304 Response code failure with java script Application

You Mentioned "Which caused server respond with 304 response code "

Hence i assuming the web requests are not properly handled by the web server, i have seen this in the past with ajax calls[XMLHttpRequest].

Also, you can try the below irule on the VS

when HTTP_REQUEST { 
if { [HTTP::header exists If-Modified-Since] } { 
   CACHE::disable 
} 
}