Non-standard: This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.
msCachingEnabled method gets the current caching state for an XMLHttpRequest.
This proprietary method is specific to Internet Explorer and Microsoft Edge.
Type: boolean. If true,
XMLHttpRequest is cached to disk. If false, it is not written to disk.