Confirm the Ending...match arg2 string with end of arg1 string...or don't...

endConfirm.js

function confirmEnding(str, target) {
  var fragCount = target.length,
      chunk = str.substring(str.length - fragCount);
  if (chunk === target) {
    return true;
  } else { return false; }
}

confirmEnding("Walking on water and developing software from a specification are easy if both are frozen", "specification");

Or with a ternary:

function confirmEnding(str, target) {
  var fragCount = target.length,
      chunk = str.substring(str.length - fragCount),
      result = (chunk === target) ? true : false;
  return result;
}

confirmEnding("Walking on water and developing software from a specification are easy if both are frozen", "specification");