Handle window scroll event in greasemonkey script - javascript

I need some advice. I have a web page and want to extend it's functionality with greasemonkey script and firefox.
When page has loaded I need run custom function during user's page scrolling (with mouse whell or scrollbar). I want show some div block when user scrolling down and hide it when he scrolling to the top.
But I met some problem - I couldn't assign event handler to the onscroll event. I use next part of the code:
function showFixedBlock(){ ... }
function onScrollStart(){ ... showFixedBlock(); ... }
window.onscroll = onScrollStart;
I test this piece of code on my test html page and it works, but when I copy it into greasemonkey, script doesn't work.
Should I assign onscroll event handler during page loading? As I know greasemonkey execute it's scripts when page has loaded? Is it the reason of the problem?
Is there some additional requirments to handle 'onscroll' event? How can I do that?
Thanks.

I may be wrong, but I think that this should work:
unsafeWindow.onscroll = onScrollStart;
or
window.addEventListener("scroll", onScrollStart, false);
You should really use the latter example.

Related

Javascript event listener to ArrowDown - Stop page scrolling

I have a hopefully rather simple Javascript question for you. I have a scrollable, static page which can show/hide a full frame overlay (hiding the whole page) using z-index. When the overlay is shown I create a new event listener to "keydown" in which I for example check for "ArrowDown". When the overlay is hidden, the listener is unsubscribed.
This works beautifully, except that the page below the overlay keeps scrolling up and down as it normally would. I thought I could stop that by using
event.stopPropagation()
which, however, does not help. How can I approach this?
Event.stopPropagation() Prevents the event from bubbling up the DOM, but does not stop the browsers default behaviour.
event.preventDefault();
this should work as it stops the browsers default behaviour.

IE error window.onload does not fire consistently

I am trying to implement the jQuery orbit slider. I have a div tag that contains several images. The problem I am encountering is the orbit() function is on occasion being called before all the images have loaded. I have tried to solve this by surrounding the orbit function call as follows:
window.onload = function(){jQuery('#img-container').orbit()}
This should ensure that orbit is only called after the page and all the content (including the necessary images) have loaded. However, the onload event is not consistently firing because the image slider does not always load. I notice that if I clear the cache and navigate to the page, then the onload event does not fire, and thus orbit never fires.
Other things I have tried:
I have also tried jQuery(window).load() which was unsuccessful. I also tried iterating over each individual image in the container with the .load() function but was not successful. I have been able to resolve this issue on Chrome and FF using something similar to this approach: jquery .one() load and error events not working
Does anyone have any other suggestions to fix this in IE?
ADDITIONAL INFO: I did a test where I use deelay.me to delay the image by a few seconds and doing so made the onload function work consistently. It's only when the image loads quickly that the onload doesn't seem to fire
The proper way to do this in jQuery using the jQuery function:
$(function(){
//onload stuff here...
});
That should work in IE as well as other browsers.

pagebeforehide event fired just for "inner" page transitions

I need to do something when leaving page (page '#first').
It's really simple:
$(document).on('pagebeforehide', '#first', function(event, ui) {alert('leaving page');});
No problem when I leave page by "inner" links something like this one:
Open something
here event fired and handler executed.
But when I want to open external link like this one:
Open something
here event not fired and handler not executed.
Doesn't matter is page content simple or complex - I found that this depends only on fact whether link inner or external.
What's wrong?
rel="external" means that page will be opened as an external page and all previous page content (including its scripts) will be lost, that will also trigger a full page refresh so your pagebeforehide event is not going to trigger because it will no longer exist.
jQuery Mobile page events can occur only during normal page changes. Basically what I want to say is you need to go to the other jQuery Mobile page for this event to trigger. In your case you are forcing app to do a full page refresh, at this point, page refresh will occur before pagebeforehide event.
EDIT :
While there isn't any crossbrowser solution for this you can always cheat.
Instead of having href link inside your button, replace your link http://www.google.com with # and add it an id so we can identify it, like this:
Open something
Now add a click event to this button and do what ever needs to be done before changing page to www.google.com:
$(document).on('click', '#change-page', function(){
// Do something here then change page
});
Or link your button to another dummy inner page (use this inner page only for this purpose), catch pagebeforehide on it:
$(document).on('pagebeforehide ', function(){
// Again do something here and manualy change the page
});

IE6 Click on binding event before document.ready destroys the binding?

Hey, So this is a rather weird issue, so what we have is a site that the javascript is at the bottom of the page. The html loads first and then we $(document).ready() element events. The issue I have right now is in IE6 (Stupid I know) where if you click on the item that is about to or during the loading of the page, will destroy the binding event. If you wait for the page to fully load then it runs the page correctly.
What I thought of so far:
Create an overlay on the page and then on document.ready remove it so that the click events aren't becoming broken.
Your probably thinking why don't you just push the JS files into the header? Well tuff-noogies can't do that either. (That might help)
Let me know what you think.
Thanks,
$(document).ready() is only executed after the page is loaded. So during the page load, $(document).ready() is still not called and events are still not bound.
The solution is to bind the events as soon as elements appear on the page. It's a bit ugly, but for slow connections, it might be the only way.

Javascript/jQuery: does anybody already created a loading fixed div on top 100%:100% of the page with jquery?

i used sometimes a 'loading' method with the javascript onload & onunloadbody events.(www.restaurantebarocortico.com)
Now i'm learning jQuery, and i used the $(document).ready & $(window).unload to replace the old events, but the unload event isn't working correctly.
Does anybody knows another method to call a function on unload? And, if needed, a method to break the unload and do some effect (, i will need this to put an effect showing the loading div on unload).
the flow of the loading div:
it appears on the top of everything (without effect) with an ajax-loader gif at the middle center.
when document is ready, hide it with jQuery function (slow effect)
when document/window is unloading, show it with jQuery function (slow effect again), and break for a while the event (or sleep the time of the effect).
Thanks and sorry my english :P
José Moreira
You cannot prevent an unload or beforeunload event. If you could, people would abuse it to make tabs unclosable.

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