Different behaviours of treating \ (backslash) in the url by FireFox and Chrome
The unified solution to deal with backslash in a URL is to use %5C. RFC 2396 did not allow that character in URLs at all (so any behavior regarding that character was just error-recovery behavior). RFC 3986 does allow it, but is not widely implemented, not least because it's not exactly compatible with existing URL processors.
Chrome, in particular, does the same thing as IE: assumes you meant a forward slash any time you type a backslash, as you discovered, because that's what Windows file paths do.
This backslash auto conversion issue has fixed in Chrome version >= 53.0.2785.116.
Now the backslashes are treated properly as %5C.