I am chaging the background of the page using mousewheel. I only want to trigger the mousewheel event once 1000ms, so for that I am using a debounce function.
Before I added the debounce function and used e.preventDefault() it prevented the scroll from working. However, now that I have added the debounce function this no longer works and the user can scroll the page again.
Please see code below.
$(document).ready(function() {
$(document).on('mousewheel DOMMouseScroll',debounce(function(e){
e.preventDefault();
//code to change the background image
}, 1000))
});
function debounce(fn, delay) {
var timer = null;
return function () {
var context = this, args = arguments;
clearTimeout(timer);
timer = setTimeout(function () {
fn.apply(context, args);
}, delay);
};
then build it like this:
$(document).ready(function() {
var changeBackground = debounce(function(e){
//code to change the background image
}, 1000)
$(document).on('mousewheel DOMMouseScroll',debounce(function(e){
e.preventDefault();
changeBackground(e);
})
});
Related
I have a function which will take some time to run on click event.
Following is merely an example and setTimeout is there only to simulate time it may take to run it. How can I ensure when a user click on an item any previous running function(s) is(are) cancelled and only the latest onclick function is fired?
i.e. if a user clicked on it 10 times. I want to only execute the only the 10th click not the 9 clicks before.
I am hoping for a pure/vanilla js solution... NOT jQuery
(function () {
var nav = document.querySelector('.nav__toggle');
var toggleState = function (elem, one, two) {
var elem = document.querySelector(elem);
elem.setAttribute('data-state', elem.getAttribute('data-state') === one ? two : one);
};
nav.onclick = function (e) {
setTimeout(function(){
toggleState('.nav ul', 'closed', 'open');
}, 5000);
e.preventDefault();
};
})();
fiddle: http://jsfiddle.net/6p94p48m/
You need to debounce your click handler.
var button = document.getElementById("debounced");
var clickHandler = function() {
alert('click handler');
}
var debounce = function(f, debounceTimeout) {
var to;
return function() {
clearTimeout(to);
to = setTimeout(f, debounceTimeout);
}
}
button.addEventListener('click', debounce(clickHandler, 5000));
<button id="debounced" href="#">debounced</button>
Or use underscore/lodash https://lodash.com/docs#debounce
I have an image gallery that rotates through the rotator class divs on www.creat3dprinters.com that pauses on mouseenter and then fires again 1 second after mouseleave.
However, if a user moves the mouse in and out of the rotator class div quickly the function calls stack up and the visible changes until the 'stack' is completed.
I want the 1 second delay that has not been completed to be cancelled on the 2nd and subsequent mouseenter so that this does not happen.
I have tried using clearTimeout within the mouseenter function but it does not seem to work.
I know there is also the stop() function but that did not work either.
Any suggestions greatly appreciated.
jQuery(document).ready(function () {
var initList = setInterval('RotateIt()', 4000);
$('.rotator').mouseenter(function () {
clearInterval(initList);
}).mouseleave(function () {
timeout = setTimeout(function () {
RotateIt()
}, 1000);
initList = setInterval('RotateIt()', 4000);
})
});
function RotateIt() {
clearTimeout(timeout);
if ($('#rotator-visible').next('.rotator').length == 0) {
$('.rotator:first').attr('id', 'rotator-visible');
$('.rotator:last').removeAttr("id");
} else {
$('#rotator-visible').removeAttr("id").next('.rotator').attr("id", "rotator-visible");
}
}
If a user moves the mouse in and out of the rotator class div quickly the function calls stack up
Then clearTimeout it - and in exactly that place, not only in the delayed RotateIt. The simplest solution would be to call clearTimeout every time before setTimeout, so that you can be sure there is only one active timeout at once.
jQuery(document).ready(function($) {
var initList = setInterval(rotateIt, 4000),
delay = null;
$('.rotator').mouseenter(function(e) {
clearInterval(initList);
}).mouseleave(function(e) {
clearTimeout(delay);
delay = setTimeout(function () {
rotateIt();
initList = setInterval(rotateIt, 4000);
}, 1000);
})
});
function rotateIt() {
if ($('#rotator-visible').next('.rotator').length == 0) {
$('.rotator:first').attr('id', 'rotator-visible');
$('.rotator:last').removeAttr("id");
} else {
$('#rotator-visible').removeAttr("id").next('.rotator').attr("id", "rotator-visible");
}
}
I have a piece of code that hides an element on mouseout.
The code looks like this:
var myMouseOutFunction = function (event) {
setTimeout(function () {
$(".classToHide").hide();
$(".classToShow").show();
}, 200);
};
This produces a result very close to what I want to do. However, I want to wait the time on the timeout (in this case 200 ms) then check to see if my mouse is still "out" of the element. If it is, I want to do .hide() and .show() on the desired elements.
I want to do this because if a user slightly mouses out then quickly mouses back in, I don't want the elements to flicker (meaning: hide then show real quick) when the user just wants to see the element.
Assign the timeout's return value to a variable, then use clearTimeout in the onmouseover event.
Detailing Kolink answer
DEMO: http://jsfiddle.net/EpMQ2/1/
var timer = null;
element.onmouseout = function () {
timer = setTimeout(function () {
$(".classToHide").hide();
$(".classToShow").show();
}, 200);
}
element.onmouseover = function () {
clearTimeout(timer);
}
You should use mouseenter and mouseleave of jquery. mouseenter and mouseleave will get called only once.and use a flag if to check if mouseenter again called.
var isMouseEnter ;
var mouseLeaveFunction = function (event) {
isMouseEnter = false;
setTimeout(function () {
if(isMouseEnter ){ return;}
$(".classToHide").hide();
$(".classToShow").show();
}, 200);
};
var mouseEnterFunction = function(){
isMouseEnter = true;
}
Use a boolean flag:
var mustWait = true;
var myMouseOutFunction = function (event) {
setTimeout(function () {
if(mustWait){
mustWait = false;
}
else{
$(".classToHide").hide();
$(".classToShow").show();
mustWait = true;
}
}, 200);
};
I need a function that executes a function while a button is pressed and stops executing when the button is let go
$('#button').--while being held down--(function() {
//execute continuously
});
I believe something like this would work:
var timeout, clicker = $('#clicker');
clicker.mousedown(function(){
timeout = setInterval(function(){
// Do something continuously
}, 500);
return false;
});
$(document).mouseup(function(){
clearInterval(timeout);
return false;
});
See this demo: http://jsfiddle.net/8FmRd/
A small modification to the original answer:
$('#Clicker').mousedown(function () {
//do something here
timeout = setInterval(function () {
//do same thing here again
}, 500);
return false;
});
$('#Clicker').mouseup(function () {
clearInterval(timeout);
return false;
});
$('#Clicker').mouseout(function () {
clearInterval(timeout);
return false;
});
With the mouseout event on the Clicker it stops when you move your mouse out of the click area.
The reason why I suggest to do the same thing twice is to get a smoother effect. If you don't do it once before the timeout is set it will be a delay of, in this case, 500ms before something happens.
Here's a pure JavaScript implementation of the supplied solutions which has extended support for touch screens. You supply the id, action to perform (function(){}) and the interval (ms) to repeat the action. Note that this implementation will also execute the action immediately, rather than waiting for the interval to lapse.
// Configures an element to execute a function periodically whilst it holds the user's attention via a mouse press and hold.
function assertPeriodicPress(id, action, interval) {
// Listen for the MouseDown event.
document.getElementById(id).addEventListener('mousedown', function(ev) { action(); timeout = setInterval(action, interval); return false; }, false);
// Listen for mouse up events.
document.getElementById(id).addEventListener('mouseup', function(ev) { clearInterval(timeout); return false; }, false);
// Listen out for touch end events.
document.getElementById(id).addEventListener('touchend', function(ev) { clearInterval(timeout); return false; }, false);
}
$.fn.click2=function(cb,interval){
var timeout;
if(!interval) interval=100;
$(this).mousedown(function () {
var target=this;
timeout = setInterval(function(){
cb.apply(target);
}, interval);
return false;
}).mouseup(function () {
clearInterval(timeout);
return false;
}).mouseout(function () {
clearInterval(timeout);
return false;
});
}
I'd like to do some fancy jQuery stuff when the user scrolls the page. But I have no idea how to tackle this problem, since there is only the scroll() method.
Any ideas?
You can make the scroll() have a time-out that gets overwritten each times the user scrolls. That way, when he stops after a certain amount of milliseconds your script is run, but if he scrolls in the meantime the counter will start over again and the script will wait until he is done scrolling again.
Update:
Because this question got some action again I figured I might as well update it with a jQuery extension that adds a scrollEnd event
// extension:
$.fn.scrollEnd = function(callback, timeout) {
$(this).on('scroll', function(){
var $this = $(this);
if ($this.data('scrollTimeout')) {
clearTimeout($this.data('scrollTimeout'));
}
$this.data('scrollTimeout', setTimeout(callback,timeout));
});
};
// how to call it (with a 1000ms timeout):
$(window).scrollEnd(function(){
alert('stopped scrolling');
}, 1000);
<script src="https://code.jquery.com/jquery-3.5.1.min.js" integrity="sha256-9/aliU8dGd2tb6OSsuzixeV4y/faTqgFtohetphbbj0=" crossorigin="anonymous"></script>
<div style="height: 200vh">
Long div
</div>
Here is a simple example using setTimeout to fire a function when the user stops scrolling:
(function() {
var timer;
$(window).bind('scroll',function () {
clearTimeout(timer);
timer = setTimeout( refresh , 150 );
});
var refresh = function () {
// do stuff
console.log('Stopped Scrolling');
};
})();
The timer is cleared while the scroll event is firing. Once scrolling stops, the refresh function is fired.
Or as a plugin:
$.fn.afterwards = function (event, callback, timeout) {
var self = $(this), delay = timeout || 16;
self.each(function () {
var $t = $(this);
$t.on(event, function(){
if ($t.data(event+'-timeout')) {
clearTimeout($t.data(event+'-timeout'));
}
$t.data(event + '-timeout', setTimeout(function () { callback.apply($t); },delay));
})
});
return this;
};
To fire callback after 100ms of the last scroll event on a div (with namespace):
$('div.mydiv').afterwards('scroll.mynamespace', function(e) {
// do stuff when stops scrolling
$(this).addClass('stopped');
}, 100
);
I use this for scroll and resize.
Here is another more generic solution based on the same ideas mentioned:
var delayedExec = function(after, fn) {
var timer;
return function() {
timer && clearTimeout(timer);
timer = setTimeout(fn, after);
};
};
var scrollStopper = delayedExec(500, function() {
console.log('stopped it');
});
document.getElementById('box').addEventListener('scroll', scrollStopper);
I had the need to implement onScrollEnd event discussed hear as well.
The idea of using timer works for me.
I implement this using JavaScript Module Pattern:
var WindowCustomEventsModule = (function(){
var _scrollEndTimeout = 30;
var _delayedExec = function(callback){
var timer;
return function(){
timer && clearTimeout(timer);
timer = setTimeout(callback, _scrollEndTimeout);
}
};
var onScrollEnd = function(callback) {
window.addEventListener('scroll', _delayedExec(callback), false);
};
return {
onScrollEnd: onScrollEnd
}
})();
// usage example
WindowCustomEventsModule.onScrollEnd(function(){
//
// do stuff
//
});
Hope this will help / inspire someone
Why so complicated? As the documentation points out, this http://jsfiddle.net/x3s7F/9/ works!
$('.frame').scroll(function() {
$('.back').hide().fadeIn(100);
}
http://api.jquery.com/scroll/.
Note: The scroll event on Windows Chrome is differently to all others. You need to scroll fast to get the same as result as in e.g. FF. Look at https://liebdich.biz/back.min.js the "X" function.
Some findings from my how many ms a scroll event test:
Safari, Mac FF, Mac Chrome: ~16ms an event.
Windows FF: ~19ms an event.
Windows Chrome: up to ~130ms an event, when scrolling slow.
Internet Explorer: up to ~110ms an event.
http://jsfiddle.net/TRNCFRMCN/1Lygop32/4/.
There is no such event as 'scrollEnd'. I recommend that you check the value returned by scroll() every once in a while (say, 200ms) using setInterval, and record the delta between the current and the previous value. If the delta becomes zero, you can use it as your event.
There are scrollstart and scrollstop functions that are part of jquery mobile.
Example using scrollstop:
$(document).on("scrollstop",function(){
alert("Stopped scrolling!");
});
Hope this helps someone.
The scrollEnd event is coming. It's currently experimental and is only supported by Firefox. See the Mozilla documentation here - https://developer.mozilla.org/en-US/docs/Web/API/Document/scrollend_event
Once it's supported by more browsers, you can use it like this...
document.onscrollend = (event) => {
console.log('Document scrollend event fired!');
};
I pulled some code out of a quick piece I cobbled together that does this as an example (note that scroll.chain is an object containing two arrays start and end that are containers for the callback functions). Also note that I am using jQuery and underscore here.
$('body').on('scroll', scrollCall);
scrollBind('end', callbackFunction);
scrollBind('start', callbackFunction);
var scrollCall = function(e) {
if (scroll.last === false || (Date.now() - scroll.last) <= 500) {
scroll.last = Date.now();
if (scroll.timeout !== false) {
window.clearTimeout(scroll.timeout);
} else {
_(scroll.chain.start).each(function(f){
f.call(window, {type: 'start'}, e.event);
});
}
scroll.timeout = window.setTimeout(self.scrollCall, 550, {callback: true, event: e});
return;
}
if (e.callback !== undefined) {
_(scroll.chain.end).each(function(f){
f.call(window, {type: 'end'}, e.event);
});
scroll.last = false;
scroll.timeout = false;
}
};
var scrollBind = function(type, func) {
type = type.toLowerCase();
if (_(scroll.chain).has(type)) {
if (_(scroll.chain[type]).indexOf(func) === -1) {
scroll.chain[type].push(func);
return true;
}
return false;
}
return false;
}