How to get the jQuery $.ajax error response text?

Question

Try:

error: function(xhr, status, error) {
  var err = eval("(" + xhr.responseText + ")");
  alert(err.Message);
}

For me, this simply works:

error: function(xhr, status, error) {
  alert(xhr.responseText);
}

Look at the responseText property of the request parameter.

As ultimately suggested by this other answer and it's comments on this page:

error: function(xhr, status, error) {
  var err = JSON.parse(xhr.responseText);
  alert(err.Message);
}