From https://docs.ckeditor.com/ckeditor4/docs/#!/api/CKEDITOR.editor-event-change
If it is important not to get the change event fired too often, you should compare the previous and the current editor content inside the event listener. It is not recommended to do that on every change event.
I don't understand the above ... is there possibly a typo?
Is it trying to say that a call such as checkDirty on every change event could result in poor performance?
Would using an interval timer be a good approach to limit the number of checkDirty calls made.
For example, do not call checkDirty unless at least 1 second had passed from its last invocation?
The use case I have is enabling or disabling a save button based on the editor content differing from its last saved state.
I deal with this situation by always having the save button enabled and:
1) Every time a user presses the save button, I alert him that the contents have been saved and I clear the dirty flag:
CKEDITOR.instances.editor1.resetDirty();
2) I register an onbeforeunload event handler to alert him if he tries to exit the webpage having unsaved data:
window.onbeforeunload = function() {
if (CKEDITOR.instances.editor1.checkDirty()) {
return 'You will lose the changes made in the editor if you don't save them.';
}
}
Related
I am using the "Simple custom control to add infinite scrolling to repeat or views" available as snippet on OpenNTF.
This works but incorrect, this is what happens:
When you reach the bottom of screen a pager control gets triggered and an AJAX call is send.
However you are still at the bottom of the screen so again the pager control gets triggered and a second ajax call is send. (check the XHR requests in your browser with firefox or something).
So you requested for 1 additional set of values and get 2 returned.
Sometimes the second ajax request is finished earlier than the first and then the sorting in the repeat control is messed up.
I first tried to set a timeout on the JS call e.g.
$(window).scroll(function() {
if ($(window).scrollTop() == $(document).height() - $(window).height()) {
setTimeout(function() {
$(".infiniteScroll ul li a").click();
}, 4000);
}
});
but I have to set the timeout to a large amount of milliseconds and sometimes 4000 is not sufficient.
I wonder if there is an option to chain the ajax calls for the pager control or disable temporarily the trigger?
I found out the problem lies with the way the infinite scroll is triggered: when reaching the bottom of the window.
Then, no state is set (e.g. loading) so before the results of the first trigger are returned a second or third trigger could be fired.
What is a generally accepted way to validate preference values in a Firefox extension, specifically when using the prefwindow mechanism in XUL?
I am introducing some new preferences in one of my extensions that I would like to validate before the preferences window is closed. If there's an error, the user should be allowed to correct the issue, and then proceed. I see that the prefwindow element has two potentially useful functions to help in this regard:
onbeforeaccept
ondialogaccept
The former seems to have an associated bug (Bug 474527) that prevents the prefwindow from remaining open when returning false from that function. This is bad in that it doesn't give the user an opportunity to immediately correct their mistake.
The latter appears to have the problem that the preferences get saved prior to exiting, which leaves the preferences in a bad state internally.
In addition, the prefwindow mechanism supports the browser.preferences.instantApply option, in which preference values are written immediately upon updating the associated control. This makes validation extra tricky. Is there a clean way to validate custom preferences in a Firefox extension, allowing the user to correct any potential mistakes?
Normally you would want to validate the preferences when they are changed. That's something that onchange attribute (and the corresponding change event) is good for:
<preference name="preference.name" onchange="validate(this);"/>
The event is fired after the preference value changes. There are two drawbacks:
In case of instantApply the new preference value is already saved, too late to validate and decline.
For text fields the preferences are saved every time a new character is typed. This becomes ugly if you report validation failure while the user is still typing.
You can solve the first issue by intercepting the change events for the actual input fields. For example, for a text field you would do:
<input preference="preference.name"
oninput="if (!validate(this)) event.stopPropagation();"
onchange="if (!validate(this)) { event.stopPropagation(); this.focus(); }"/>
So changes that don't validate correctly don't bubble up to the <prefpane> element and don't get saved. The events to listen to are: input and change for text fields, command for buttons and checkboxes, select for the <colorpicker> element.
The second issue is tricky. You still want to validate the input when it happens, showing the message immediately would be bad UI however. I think that the best solution is to assume for each input field initially that it is still "in progress". You would only set a flag that the value is complete when you first see a blur event on the field. That's when you can show a validation message if necessary (ideally red text showing up in your preference page, not a modal prompt).
So to indicate what the final solution might look like (untested code but I used something like that in the past):
<description id="error" hidden="true">Invalid preference value</description>
<input preference="preference.name"
_errorText="error"
onblur="validate(event);"
oninput="validate(event);"
onchange="validate(event);/>
<script>
function validate(event)
{
// Perform actual validation
var field = event.target;
var valid = isValid(field);
// If this is the blur event then the element is no longer "in progress"
if (event.type == "blur")
{
field._inputDone = true;
if (!valid)
field.focus();
}
// Prevent preferences changing to invalid value
if (!valid)
event.stopPropagation();
// Show or hide error text
var errorText = document.getElementById(field.getAttribute("_errorText"));
errorText.hidden = valid || !field._inputDone;
}
</script>
If you want to validate values as soon as the field is changed so you can handle the instantApply case, you could hook into the change events for the individual fields (e.g. oninput for a textbox). Display an error message and force the focus back to the field if the value is invalid. You can either set it back to a valid value automatically or block the user from closing the dialog until it is fixed.
I have a unique situation over here. I have a button on a form which produces a popup if there are some errors in the form. [I know this is not good practice, but the developers of the product would not be changing that behavior!] The form navigates to a different page if all the required fields are correctly populated. Now, I need to write a script in order to click the "Submit" button on the form which either might produce a popup or navigate to the next page.
I have the used the click_no_wait on the "Submit" button and handled the popup using AutoIt as per Javascript Popups in Watir. Now, if all the information is valid and the form navigates to the next page, I use a delay in the script by following some of the techniques described in How to wait with Watir. I am using a Watir::wait_until() to wait in the script.
Now sometimes because of some network issues, it takes time to go to the next page (report-generation) page when the form is submitted and thus the script fails because of the timeout value specified in the wait_until.
I was wondering whether there is a way to intercept the onload event of the HTML page in Watir, since the onload event isn't fired until the entire page is loaded. By that way I could have an accurate estimate of the timeout value and not experiment with it. Thus, my script will pass 100% rather than say 98% right now.
Thanks for any help on this topic.
You could try setting up a rescue for the time out, then looping a reasonable amount of times (2 or 3?) if it encounters a timeout.
E.g.
# All your button clicking and autoit stuff here
i = 0
begin
b.wait_until{ # the thing you're waiting to happen }
rescue TheSpecificTimeOutException
# Sorry I can't remember it, the command prompt will tell you exactly
# which one
if i < 3
i += 1
retry
else
raise
end
end
I'm sure i'll have messed something up in the above, or there'll be more concise ways of doing it, but you get the idea. When it times out, give it another few tries before giving up.
I have an app that has several different types of form elements which all post data to the server with jQuery AJAX.
What I want to do is:
Show a loader during AJAX transmission
Prevent the user from submitting twice+ (clicking a lot)
This is easy to do on a one off basis for every type of form on the site (comments, file upload, etc). But I'm curious to learn if that is a more global way to handle this?
Something that's smart enough to say:
If a form is submitting to the server and waiting for a response, ignore all submits
Show a DISABLED class on the submitted / clicked item
Show a loading class on the class="spinner" which is closest to the submit item clicked
What do you think? Good idea? Done before?
Take a look at the jQuery Global Ajax Event Handlers.
In a nutshell, you can set events which occur on each and every AJAX request, hence the name Global Event Handlers. There are a few different events, I'll use ajaxStart() and ajaxComplete() in my code sample below.
The idea is that we show the loading, disable the form & button on the ajaxStart() event, then reenable the form and hide the loading element inside the ajaxComplete() event.
var $form = $("form");
$form.ajaxStart(function() {
// show loading
$("#loading", this).show();
// Add class of disabled to form element
$(this).addClass("disabled");
// Disable button
$("input[type=submit]", this).attr("disabled", true);
});
And the AJAX complete event
$form.ajaxComplete(function() {
// hide loading
$("#loading", this).hide();
// Remove disabled class
$(this).removeClass("disabled");
// Re-enable button
$("input[type=submit]", this).removeAttr("disabled");
});
You might need to attach to the ajaxError event as well in case an AJAX call fails since you might need to clean up some of the elements. Test it out and see what happens on a failed AJAX request.
P.S. If you're calling $.ajax or similar ($.getJSON), you can still set these events via $.ajaxStart and $.ajaxComplete since the AJAX isn't attached to any element. You'll need to rearrange the code a little though since you won't have access to $(this).
I believe you have to do 2 for sure and 3 to improve usability of your app. It is better to keep backend dumb but if you have a security issue you should handle that too.
I've been working on Chrome Extension for a website for the past couple of days. It's coming along really nicely but I've encountered a problem that you might be able to help with.
Here's an outline of what the extension does (this functionality is complete):
A user can enter their username and password into the extensions popup - and verify their user account for the particular website
When a user browses http://twitter.com a content script is dynamically included that manipulates the DOM to include an extra button next to each tweet displayed.
When a user clicks this button they are presented with a dialog box
I've made a lot of progress but here is my problem:
When a user visits Twitter the content script is activated and all tweets on the page get my new button - but if the user then clicks 'More...' and dynamically loads the next 20 tweets... these new additions to the page DOM do not get affected by the content script (because it is already loaded).
I could add an event listener to the 'More...' button so it then triggers the original content script again (and adds the new button) but i would have to predict the length of twitter's ajax request response.
I can't tap into their Ajax request that pulls in more tweets and call my addCurateButton() function once the request is complete.
What do you think is the best solution? (if there is one)
What you want to do is to re-execute your content-script every time the DOM is changed. Luckily there is an event for that. Have a look at the mutation event called DOMNodeInserted.
Rewrite your content script so that it attaches an event listener to the body of the DOM for the DOMNodeInserted event. See the example below:
var isActive = false;
/* Your function that injects your buttons */
var inject = function() {
if (isActive) {
console.log('INFO: Injection already active');
return;
}
try {
isActive = true;
//inject your buttons here
//for the sake of the example I just put an alert here.
alert("Hello. The DOM just changed.");
} catch(e) {
console.error("ERROR: " + e.toString());
} finally {
isActive = false;
}
};
document.body.addEventListener("DOMNodeInserted", inject, false);
The last line will add the event listener. When a page loads the event is triggered quite often so you should define a boolean (e.g. var isActive), that you initialize to false. Whenever the inject function is run check whether isActive == true and then abort the injection to not execute it too often at the same time.
Interacting with Ajax is probably the hardest thing to coax a content script to do, but I think you’re on the right track. There are a couple different approaches I’ve taken to solving this problem. In your case, though, I think a combination of the two approaches (which I’ll explain last) would be best.
Attach event listeners to the DOM to detect relevant changes. This solution is what you’ve suggested and introduces the race condition.
Continuously inspect the DOM for changes from inside a loop (preferably one executed with setInterval). This solution would be effective, but relatively inefficient.
The best-of-both-worlds approach would be to initiate the inspection loop only after the more button is pressed. This solution would both avoid the timing issue and be efficient.
You can attach an event-handler on the button, or link that is used for fetching more results. Then attach a function to it such that whenever the button is clicked, your extension removes all the buttons from DOM and starts over inserting them, or check weather your button exists in that particular class of DOM element or not and attach a button if it doesn't.