I'm developing a web application开发者_开发百科 which requires long-running Ajax requests. Unfortunately, under Firefox, pressing Escape during a request has the drawback of killing the request and any information it was holding. This is rather annoying, as this can lead to all sorts of nasty complications if this happens at the wrong time. Therefore, I would like to deactivate this feature.
My first reflex was to intercept keypresses at the boundaries of <body>, to ensure that they would not reach the window. For this purpose, I installed a [keypress] event handler, just for events whose [keyChar] is 27, and had it invoke [stopPropagation] and [preventDefault]. And for a time, it looked like this was working.
Then, I realized that it wouldn't work when the user hadn't clicked anywhere on the window, as <body> event handlers never received the event. I tried to attach my handler to <document> or <window> to no avail, so I eventually ended up adding a [load] event handler and had it force focus to <body>. And for a time, it looked like this was working.
Then, I realized that when the user was editing an <input>, for some reason, once again, the <body>, <document> or <window> event handler never seem to receive the event. So, I added yet another [keypress] handler, intercepting with [preventDefault] on the <input> when the [keyChar] is 27.
For the moment, it looks like it's working. However, with the history of this bug in my application, I'm a tad pessimistic.
So, I'm wondering if there's a better -- and reproducible -- method. Recall that the bug seems to appear only in Firefox, so I'm quite willing to take a Firefox-only approach here.
I'd be worried about other nasty complications that will happen when the users choose a bookmark or otherwise navigate away in the middle of the request. You might want to look at why you're using long running requests and see if that's something you can change...
If it isn't something you can change (or even if you can) you should look at why your requests aren't fault tolerant. Is there a way to put the communication into transactions, and roll the latest one back if the connection is interrupted?
I know this is kind of an old thread but there's an active bug logged against Mozilla regarding this issue (which I'm also facing). See https://bugzilla.mozilla.org/show_bug.cgi?id=614304 for more info.
One suggestion from this bug is to intercept and prevent the ESC key press at the window level (as also mentioned by OP):
window.addEventListener('keydown', function(e) {(e.keyCode == 27 && e.preventDefault())});
This might have unwanted side-effects though.
![Interactive visualization of a graph in python [closed]](https://www.devze.com/res/2023/04-10/09/92d32fe8c0d22fb96bd6f6e8b7d1f457.gif)
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