Doubling Backslashes In JavaScript - It's Unorthodox, But It Works...

I've spent the last two hours trying every other solution listed, to
no avail: this works, so I'm sharing it for the other folks who
couldn't find a solution other than switching to another language.

var fileString = "mydevfolderfolder2folder3file.txt";

var myPat = /%5C/g; //this is using regular expression to
define the escaped version of a backslash

fileString = escape(fileString);
fileString = fileString.replace(myPat,"%5C%5C");
fileString = unescape(fileString);

fileString now equals "\mydevfolderfolder2folder3 file.txt"