CODEWITHSUNDEEP
javascriptxmlhttprequestonreadystatechange
yoduoy
yoduoy

Reputation: 21

XMLHttpRequest onreadystatechange long delay between readyState 1 and 2

My JS code is sending out requests and monitors "xhr.onreadystatechange". Sometimes it will collect the following logs, which are expected:

timestamp   event   method  readyState  status
1/9/2018 9:08:43.474    xhr_readystatechange    POST    1   0
1/9/2018 9:08:46.432    xhr_readystatechange    POST    2   200
1/9/2018 9:08:46.432    xhr_readystatechange    POST    3   200
1/9/2018 9:08:46.433    xhr_readystatechange    POST    4   200

Other times it will collect the following logs, which are not expected: (in this case, readyState never changed to 2 within the 22 seconds before my app timed out)

timestamp   event   method  readyState  status
1/11/2018 21:36:25.390  xhr_readystatechange    POST    1   0
1/11/2018 21:36:47.249  localSend           failed

I understand that:

My question is: if readyState changed to 1 but never changed to 2/3/4, was my POST request actually:

Note this is on IE 11.

Thanks,

Upvotes: 1

Views: 1881

Answers (1)

btooom
btooom

Reputation: 53

If readyState is 1, it only means that the method open was called. This can't say if the request was sent or not. If the method send was called, the client will make a establishment with the server. If the connection failed, the event onerror will be fired. So try to see the error message, and it will says the reason.

To answer the question. It is possible that send was not called if readyState is 1, but if you want to know the method send was called or not, you should see the code, and log the message when the method send was called. Also, if readyState is 1, and you've checked the method send was called, it means that the client started to make the establishment with the server, so it could be that the packet is on the way, and it could got stuck for some reason.

In a nutshell, readyState can't tell if the method send was called or not. The way to check that is to see the code, and make sure that the method send was called or not.

Upvotes: 1

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