I would like to extend the existing XMLHttpRequest object so that it should work with all the browsers. Now I have been trough with JS inheritance and things however before starting I would like to see good example of it.

HTML5 has upload and progress events stuff which I would like to implement in inherited new object which can behave even if the feature is not supported by not introducing JS errors to client side. So I would like to achieve something like this:

Class XMLHttpRequest{}
Class UploadXMLHttpRequest: XMLHttpRequest{}

Where additional methods can be attached to UploadXMLHttpRequest class like following.

UploadXMLHttpRequest.prototype.uploadFile = function(file){

}

Considering YUI, jQuery and others are good in market no one really wants to do this made it little difficult for me to find good resources.

I would like to extend the existing XMLHttpRequest object so that it should work with all the browsers. Now I have been trough with JS inheritance and things however before starting I would like to see good example of it.

HTML5 has upload and progress events stuff which I would like to implement in inherited new object which can behave even if the feature is not supported by not introducing JS errors to client side. So I would like to achieve something like this:

Class XMLHttpRequest{}
Class UploadXMLHttpRequest: XMLHttpRequest{}

Where additional methods can be attached to UploadXMLHttpRequest class like following.

UploadXMLHttpRequest.prototype.uploadFile = function(file){

}

Considering YUI, jQuery and others are good in market no one really wants to do this made it little difficult for me to find good resources.

• javascript
• ajax
• dom-events

• unatainable goal since not all browsers have a XMLHttpRequest class. and by not all browsers, I mean Internet explorer. What you have to do is to use those 'good in market' libraries and use their wrappers to make your ajax calls. – BiAiB Commented Feb 8, 2011 at 10:44
• 1 possible duplicate of Failed to override the getResponseHeader method on XMLHttpRequest – Marcel Korpel Commented Feb 8, 2011 at 10:44
• No i know ActiveXObject in IE and XMLHttpRequest in others. What i would like to know is what is good way i can extend the XMLHttpRequest so that i can have a clean and safe API for regular use. – Anil Namde Commented Feb 8, 2011 at 10:50
• Look at code of "good in market" libraries =) – kirilloid Commented Feb 8, 2011 at 10:55
• You can use the frameworks previously named, they have a clean safe, widely used and tested API, so unless you have good reasons, in which case it would be could to expose them here, why wouldn't you use them ? – BiAiB Commented Feb 8, 2011 at 10:58

1 Answer 1

Don't do this. XMLHttpRequest is a host object and you should not try to extend it. To quote Kangax:

Next problem with DOM extension is that DOM objects are host objects, and host objects are the worst bunch. By specification (ECMA-262 3rd. ed), host objects are allowed to do things, no other objects can even dream of. To quote relevant section ^[8.6.2]:

Host objects may implement these internal methods with any implementation-dependent behaviour, or it may be that a host object implements only some internal methods and not others.

This also means that host objects may disallow extension by using prototype.

However, as Kangax also advices, you can create a wrapper around XMLHttpRequest and do whatever you like with it.