[Octane]

Похоже каждый создает xhr-объект так, как ему хочется

jQuery 1.3.2

xhr:function(){
	return window.ActiveXObject ? new ActiveXObject("Microsoft.XMLHTTP") : new XMLHttpRequest();
},

MooTools 1.2.1

Browser.Request = function(){
	return $try(function(){
		return new XMLHttpRequest();
	}, function(){
		return new ActiveXObject('MSXML2.XMLHTTP');
	});
};

Prototype 1.6.0.2

getTransport: function() {
	return Try.these(
	  function() {return new XMLHttpRequest()},
	  function() {return new ActiveXObject('Msxml2.XMLHTTP')},
	  function() {return new ActiveXObject('Microsoft.XMLHTTP')}
	) || false;
},

Ext JS 2.2

activeX:[
	'MSXML2.XMLHTTP.3.0',
	'MSXML2.XMLHTTP',
	'Microsoft.XMLHTTP'
]

Fleegixjs

var t = [
  'Msxml2.XMLHTTP.6.0',
  'MSXML2.XMLHTTP.3.0',
  'Microsoft.XMLHTTP'
];

JavaScriptMVC 1.5.2

MVC.Ajax.factory = function(){ return window.ActiveXObject ? new ActiveXObject("Microsoft.XMLHTTP") : new XMLHttpRequest();};

AJAX.OOP 1.0.4

this._transport = (new XMLHttpRequest() || new ActiveXObject('Msxml2.XMLHTTP') || new ActiveXObject('Microsoft.XMLHTTP') || null);

June 1.1

var createXmlHttp = function()
{
///<summary>Creates an XMLHttpRequest object.</summary>
///<returns type="Object" />
    try { return new XMLHttpRequest(); } catch(ex){}
    try { return new ActiveXObject("Msxml2.XMLHTTP"); } catch(ex){}
    try { return new ActiveXObject("Microsoft.XMLHTTP"); } catch(ex) {
        return xmlHttpNotImplemented();
    }
    return null;
};

Midori (r80)

try { this.request = new XMLHttpRequest() }
catch (e)
  { try { this.request = new ActiveXObject('Msxml2.XMLHTTP') }
	catch (e)
	   { this.request = new ActiveXObject('Microsoft.XMLHTTP') }
  }

DOMAssistant 2.7.4

var XMLHttpMS = ["Msxml2.XMLHTTP.6.0", "Msxml2.XMLHTTP.3.0", "Msxml2.XMLHTTP", "Microsoft.XMLHTTP"];

Dojo

d._XMLHTTP_PROGIDS = ['Msxml2.XMLHTTP', 'Microsoft.XMLHTTP', 'Msxml2.XMLHTTP.4.0'];