​

var uriCleanup = function (str) {

​

    var cln = function (str) {

​

        try {

​

            str = decodeURIComponent(str);

            //try to decode the URI again

            return cln(str);

​

        } catch (e) {

           console.log(e)

           //if error thrown, URI contains single percent symbol

           //return the str as it was the last time it was decoded

           return str;

​

        }

​

    };

    return cln(str);

​

};

​

encodedURI = "www.thesite.com?var1=1%252526var2=false%26var3%26search=my%20search%20term%5D";

doubleEncodedURI = "www.thesite.com?var1=1%2526var2=false%2526var3%2526search=my%2520search%2520term%255D%255D";

console.log("encodedURI ", uriCleanup(encodedURI));

console.log("doubleEncodedURI ", uriCleanup(doubleEncodedURI));

console.log("%25 ", uriCleanup("%25"));