Gibberish Returned in Strings from Web Service

 Greetings!
 I have a web service (ASMX) and in it, a web method that does some work and throws an exception if the input wasn't valid.
throw new Exception(l_errMsg ?? "Invalid Input.");Back in the client script, on the error callback function, I display my error:
function GetInputErrorCallback(error)
{
// Insert the error message into the Forgot Password help window's existing content.
var errorDiv = document.getElementById('input_error');

if (errorDiv != null)
errorDiv.innerHTML = error.get_message();
}This works great.  However, if one of my error messages that's returned contains a special character, it's displayed incorrectly in the browser.
For example, if the error message were to contain the following:
That input isn?t valid!&n ...