How asynchronous is AJAX

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I have been experimenting with HTTP push. It doesn't work too well with IE so I had a look at the over hyped AJAX to see if it is any good. On the surface it is.

You can listen to the readyStateChangeEvent and get notification when new data arrives. Obviously you will have to open your XMLHttpRequest object in asynchronous mode for this to work. However there is a catch you cannot get hold of the responseXML object. It gives you a null while the responseText object is populated.

If you want to get hold of a DOM object you need to create a DOMParser and get it to parse the responseText. None of these are things that will give you nightmares what will give you a nightmare is what happens when you try to make another XMLHttpRequest while the PUSH is happening in the background. The browser freezes up.

Does that mean that there can only be one XMLHttpObject instance per window?

The mozilla javascript documentation certainly leaves much to be desired.

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