You could write your own replacement method:
String.prototype.decodeEscapeSequence = function() {
return this.replace(/\\x([0-9A-Fa-f]{2})/g, function() {
return String.fromCharCode(parseInt(arguments[1], 16));
});
};
"http\\x3a\\x2f\\x2fwww.example.com".decodeEscapeSequence()