JavaScript self-made Error object comparison

<html><head><title> JavaScript self-made Error object comparison </title></head>
<body><script type="text/javascript">

/*** Error classes ****************************************/

/* Implementation 1: The very simple one */
function MyError1(message) {
    this.name = 'MyError1';
    this.message = message;
    this.stack = (new Error()).stack;
}
MyError1.prototype = new Error;  // <-- remove this line if you do not
                                 //     want MyError1 to inherit Error

/* Implementation 2:
http://stackoverflow.com/questions/1382107/whats-a-good-way-to-extend-error-in-javascript/3535758#3535758 */
function MyError2(message, fileName, lineNumber) {
    var err = new Error();
    if (err.stack) {
        // remove one stack level:
        if (typeof(Components) != 'undefined') {
            // Mozilla:
            this.stack = err.stack.substring(err.stack.indexOf('\n')+1);
        }
        else if (typeof(chrome) != 'undefined' || typeof(process) != 'undefined') {
            // Google Chrome/Node.js:
            this.stack = err.stack.replace(/\n[^\n]*/,'');
        }
        else {
            this.stack = err.stack;
        }
    }
    this.message    = message    === undefined ? err.message    : message;
    this.fileName   = fileName   === undefined ? err.fileName   : fileName;
    this.lineNumber = lineNumber === undefined ? err.lineNumber : lineNumber;
}

/* Implementation 3:
http://blog.getify.com/2010/02/howto-custom-error-types-in-javascript/ */
var MyError3 = (function() {
   function F(){}
   function CustomError() {
      var _this = (this===window) ? new F() : this,
          tmp = Error.prototype.constructor.apply(_this,arguments)
      ;
      for (var i in tmp) {
         if (tmp.hasOwnProperty(i)) _this[i] = tmp[i];
      }
      return _this;
   }
   function SubClass(){}
   SubClass.prototype = Error.prototype;
   F.prototype = CustomError.prototype = new SubClass();
   CustomError.prototype.constructor = CustomError;
   return CustomError;
})();

/*** Run a set of tests ***********************************/

function test(name, errorObject) {
    document.write('<h3>'+ name +'</h3>');
    document.write('<p>instance of Error: ')
    document.write(errorObject instanceof Error);
    document.write('<br>instance of '+ name +': ');
    document.write(eval('errorObject instanceof '+ name));
    document.write('</p>')
    try {
        for (var key in errorObject) {
            document.write('<dl><dt>'+ key +'</dt><dd>');
            if (key == 'lineNumber') {
                document.write(errorObject.lineNumber);
                document.write(errorObject.lineNumber === test.lineNum
                               ? ' === ' : ' !== ');
                document.write(test.lineNum);
            } else {
                document.write(errorObject[key]);
            }
            document.write('</dd></dl>');
        }
    } catch (e) {
        document.write('</dd></dl>');
        document.write('<p>failed: '+ e +'</p>');
    }
    ++test.lineNum;
}
test.lineNum = (new Error()).lineNumber + 1;
try { throw new Error('message') } catch (e) {     test('Error', e) }
try { throw new MyError1('message1') } catch (e) { test('MyError1', e) }
try { throw new MyError2('message2') } catch (e) { test('MyError2', e) }
try { throw new MyError3('message3') } catch (e) { test('MyError3', e) }

</script></body></html>