Where does my page link the API

I am trying to create an intranet page using XML stuff and javascript, and I was just wondering where it gets it's function library. I mean I am creating classes like ActiveXObject and DOMParser and not only do I have no idea where to find their APIs online, I don't even understand how come I can use those objects. I don't remember including them on my webpage somehow?

I am just really confused by where the API is for certain objects that I am using readily on a webpage I am building. I still don't understand whether I should be posting a question like this in XML, DOM, or Javascript. There doesn't seem to be a clear line separting those things sometimes. Like when I use a function like getElementsByTagName, is that a javascript issue, a DOM issue, or an XML issue? HOpefully somebody can explain?

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/script56/html/js56jsobjactivexobject.asp

ActiveXObject is unique to Microsoft, so you can find that information on their website.

DOMParser and other objects/methods that you haven't written, but are apart of the browser. If you write code that is being scripted on the client side, you are assuming the client's browser supports these objects/methods. It looks like you are using objects/methods that are built in to IE.

I don't think there's ONE API that sums up the whole browser and all its components. The link I provided above contains the 'API' for lots of the functions/objects supported by IE. For an intranet solution, that should work fine since everyone will be using IE. However, if this is an internet solution, then you should be more wary as not all users will be using IE.

Hope that helps,
Sadiq.

I guess that is the step I want to take. I'd like to make my pages more versatile and at least compatible with Firefox, and making that transition from IE to Firefox has been about 10x more difficult than doing the page in the first place for IE. I can't seem to find what functions and objects fireFox allows.

Once again: Scriptable Objects (http://www.xulplanet.com/references/objref/)and: Gecko DOM Reference (http://www.mozilla.org/docs/dom/domref/)