We Keep Coding

How to keep Skrollr-Menu at an even speed?

I'm using Skrollr-menu to animate down a page on a button press using the following
HTML
<div class="trigger-scroll left">></div>
... the page i want to reveal, using scrolling ...
<section id="End" class="scroll-here">
<div class="hsContainer bottom"></div>
</section>
JavaScript
var s = skrollr.init();
skrollr.menu.init(s, {
animate: true,
//How long the animation should take in ms.
duration: function(currentTop, targetTop) {
//By default, the duration is hardcoded at 500ms.
return 18000;
//But you could calculate a value based on the current scroll position (`currentTop`) and the target scroll position (`targetTop`).
//return Math.abs(currentTop - targetTop) * 10;
},
//This event is triggered right before we jump/animate to a new hash.
change: function(newHash, newTopPosition) {
//Do stuff
},
//Add hash link (e.g. `#foo`) to URL or not.
updateUrl: false //defaults to `true`.
});
What happens when I click the button is that it works, that is not the problem.
The problem is that it seems to change speed as skrollr-menu animates the page. It starts off quite quickly, which means that the first few elements on the page (about the first 2000px) flash past without being readable. Then the speed evens out and is fine right until the last 3000px (approximately) where skrollr-menu is very slow. What I want is for the click of the button to resemble holding the down arrow on the keyboard or the scroll sidebar, which by default it seems skrollr-menu does not do.
I've tried using math equations to change the speed but the issue persists no matter what i try, and there doesn't seem to be any "simple" way to change the acceleration speed, and I suspect the problem is somewhere within the Skrollr.menu.js file, but I can't see where.
Is there any way which I can make the scrolling an even speed, rather than fast at the start and slow at the end?
Note: I'm not very experienced in JavaScript or jQuery, so it's probably something simple I've overlooked.
skrollr menu on github
https://github.com/Prinzhorn/skrollr-menu
Skrollr.menu.js
/*!
* Plugin for skrollr.
* This plugin makes hashlinks scroll nicely to their target position.
*
* Alexander Prinzhorn - https://github.com/Prinzhorn/skrollr
*
* Free to use under terms of MIT license
*/
(function(document, window) {
'use strict';
var DEFAULT_DURATION = 500;
var DEFAULT_EASING = 'sqrt';
var DEFAULT_SCALE = 1;
var MENU_TOP_ATTR = 'data-menu-top';
var MENU_OFFSET_ATTR = 'data-menu-offset';
var MENU_DURATION_ATTR = 'data-menu-duration';
var MENU_IGNORE_ATTR = 'data-menu-ignore';
var skrollr = window.skrollr;
var history = window.history;
var supportsHistory = !!history.pushState;
/*
Since we are using event bubbling, the element that has been clicked
might not acutally be the link but a child.
*/
var findParentLink = function(element) {
//We reached the top, no link found.
if(element === document) {
return false;
}
//Yay, it's a link!
if(element.tagName.toUpperCase() === 'A') {
return element;
}
//Maybe the parent is a link.
return findParentLink(element.parentNode);
};
/*
Handle the click event on the document.
*/
var handleClick = function(e) {
//Only handle left click.
if(e.which !== 1 && e.button !== 0) {
return;
}
var link = findParentLink(e.target);
//The click did not happen inside a link.
if(!link) {
return;
}
if(handleLink(link)) {
e.preventDefault();
}
};
/*
Handles the click on a link. May be called without an actual click event.
When the fake flag is set, the link won't change the url and the position won't be animated.
*/
var handleLink = function(link, fake) {
var hash;
//When complexLinks is enabled, we also accept links which do not just contain a simple hash.
if(_complexLinks) {
//The link points to something completely different.
if(link.hostname !== window.location.hostname) {
return false;
}
//The link does not link to the same page/path.
if(link.pathname !== document.location.pathname) {
return false;
}
hash = link.hash;
} else {
//Don't use the href property (link.href) because it contains the absolute url.
hash = link.getAttribute('href');
}
//Not a hash link.
if(!/^#/.test(hash)) {
return false;
}
//The link has the ignore attribute.
if(!fake && link.getAttribute(MENU_IGNORE_ATTR) !== null) {
return false;
}
//Now get the targetTop to scroll to.
var targetTop;
var menuTop;
//If there's a handleLink function, it overrides the actual anchor offset.
if(_handleLink) {
menuTop = _handleLink(link);
}
//If there's a data-menu-top attribute and no handleLink function, it overrides the actual anchor offset.
else {
menuTop = link.getAttribute(MENU_TOP_ATTR);
}
if(menuTop !== null) {
//Is it a percentage offset?
if(/p$/.test(menuTop)) {
targetTop = (menuTop.slice(0, -1) / 100) * document.documentElement.clientHeight;
} else {
targetTop = +menuTop * _scale;
}
} else {
var scrollTarget = document.getElementById(hash.substr(1));
//Ignore the click if no target is found.
if(!scrollTarget) {
return false;
}
targetTop = _skrollrInstance.relativeToAbsolute(scrollTarget, 'top', 'top');
var menuOffset = scrollTarget.getAttribute(MENU_OFFSET_ATTR);
if(menuOffset !== null) {
targetTop += +menuOffset;
}
}
if(supportsHistory && _updateUrl && !fake) {
history.pushState({top: targetTop}, '', hash);
}
var menuDuration = parseInt(link.getAttribute(MENU_DURATION_ATTR), 10);
var animationDuration = _duration(_skrollrInstance.getScrollTop(), targetTop);
if(!isNaN(menuDuration)) {
animationDuration = menuDuration;
}
//Trigger the change if event if there's a listener.
if(_change) {
_change(hash, targetTop);
}
//Now finally scroll there.
if(_animate && !fake) {
_skrollrInstance.animateTo(targetTop, {
duration: animationDuration,
easing: _easing
});
} else {
defer(function() {
_skrollrInstance.setScrollTop(targetTop);
});
}
return true;
};
var jumpStraightToHash = function() {
if(window.location.hash && document.querySelector) {
var link = document.querySelector('a[href="' + window.location.hash + '"]');
if(!link) {
// No link found on page, so we create one and then activate it
link = document.createElement('a');
link.href = window.location.hash;
}
handleLink(link, true);
}
};
var defer = function(fn) {
window.setTimeout(fn, 1);
};
/*
Global menu function accessible through window.skrollr.menu.init.
*/
skrollr.menu = {};
skrollr.menu.init = function(skrollrInstance, options) {
_skrollrInstance = skrollrInstance;
options = options || {};
_easing = options.easing || DEFAULT_EASING;
_animate = options.animate !== false;
_duration = options.duration || DEFAULT_DURATION;
_handleLink = options.handleLink;
_scale = options.scale || DEFAULT_SCALE;
_complexLinks = options.complexLinks === true;
_change = options.change;
_updateUrl = options.updateUrl !== false;
if(typeof _duration === 'number') {
_duration = (function(duration) {
return function() {
return duration;
};
}(_duration));
}
//Use event bubbling and attach a single listener to the document.
skrollr.addEvent(document, 'click', handleClick);
if(supportsHistory) {
skrollr.addEvent(window, 'popstate', function(e) {
var state = e.state || {};
var top = state.top || 0;
defer(function() {
_skrollrInstance.setScrollTop(top);
});
}, false);
}
jumpStraightToHash();
};
//Expose the handleLink function to be able to programmatically trigger clicks.
skrollr.menu.click = function(link) {
//We're not assigning it directly to `click` because of the second ("private") parameter.
handleLink(link);
};
//Private reference to the initialized skrollr.
var _skrollrInstance;
var _easing;
var _duration;
var _animate;
var _handleLink;
var _scale;
var _complexLinks;
var _change;
var _updateUrl;
//In case the page was opened with a hash, prevent jumping to it.
//http://stackoverflow.com/questions/3659072/jquery-disable-anchor-jump-when-loading-a-page
defer(function() {
if(window.location.hash) {
window.scrollTo(0, 0);
}
});
}(document, window));

The problem was the easing function found here
//Now finally scroll there.
if(_animate && !fake) {
_skrollrInstance.animateTo(targetTop, {
duration: animationDuration,
easing: _easing
});
} else {
defer(function() {
_skrollrInstance.setScrollTop(targetTop);
});
}
return true;
It seems that, even though Skrollr states that easing's default is linear (no easing), the default is ACTUALLY set to sqrt (or at least it was in my case). The problem can be solved by forcing easing to linear in skrollr.menu.init, or chaning the skrollr.menu.js file to remove easing from the function. The first of these two solutions is cleaner, and won't cause issues later.
skrollr.menu.init(s, {
duration: function(currentTop, targetTop) {return 20000;},
easing: 'linear'
});

jquery .hover() with else if statement

I want to put a little delay for onmouseout event for a group of sub items in a drop down menu. But I don't want to use css transitions.
I set it with .hover() and setTimeout method but I wanted to put it only for a specific elements in menu - in this case just for sub items so I used if else statement for them. I have no idea why this if else statement does't work.
Here is my javascript code:
var selectors =
{
element: '.main-menu li:has(ul)'
}
var opacityWorkaround = function ($element, value) {
$element.css('opacity', value);
};
var getAnimationValues = function (visible) {
var result = {
visibility: visible
};
result.opacity = visible === 'visible' ? 1 : 0;
};
var mouseActionHandler = function ($element, visible, opacityValue) {
$element
.stop()
.css("visibility", 'visible')
.animate(getAnimationValues(visible),
3000,
function () {
$(this).css("visibility", visible);
opacityWorkaround($(this), opacityValue);
});
};
var onMouseIn = function () {
var $submenu = $(this).children("ul:first");
if ($submenu) {
mouseActionHandler($submenu, 'visible', 1);
}
};
var onMouseOut = function () {
var $submenu = $(this).children("ul:first");
var $global = $('.global').children('ul');
if ($submenu) {
mouseActionHandler($submenu, 'hidden', 0);
} else if ($global) {
setTimeout(function() {
mouseActionHandler($global, 'hidden', 0);
},1500);
}
};
$(selectors.element).hover(onMouseIn, onMouseOut);
I put 1500ms delay and the $global variable is referring to sub items in menu that I want to make disapear with that delay. I wanted to achieve this when user move mouse cursor out of 'some items >' tab.
Here is my fiddle example.
http://jsfiddle.net/PNz9F/1/
Thanks in advance for any help!

In the example you have in your question $submenu always has a value so the else if statement is never run. You can check for a class instead.
var timeout;
var $submenu = $(this).children("ul:first");
var $global = $('.global').children('ul');
if ($(this).hasClass('menu-item')) {
mouseActionHandler($submenu, 'hidden', 0);
mouseActionHandler($global, 'hidden', 0);
clearTimeout(timeout);
} else if ($(this).hasClass('global')) {
timeout = setTimeout(function() {
mouseActionHandler($global, 'hidden', 0);
},1500);
}

you should be able to just use the :hover selector in your code to check whether the user is hovering over the element or not and run code accordingly

A Function to Check if the Mouse is Still Hovering an Element Every 10 Milliseconds (and run a function if it is)

I was wondering if there is a function to be run after an element (e.g. div class="myiv") is hovered and check every X milliseconds if it's still hovered, and if it is, run another function.
EDIT: This did the trick for me:
http://jsfiddle.net/z8yaB/

For most purposes in simple interfaces, you may use jquery's hover function and simply store in a boolean somewhere if the mouse is hover. And then you may use a simple setInterval loop to check every ms this state. You yet could see in the first comment this answer in the linked duplicate (edit : and now in the other answers here).
But there are cases, especially when you have objects moving "between" the mouse and your object when hover generate false alarms.
For those cases, I made this function that checks if an event is really hover an element when jquery calls my handler :
var bubbling = {};
bubbling.eventIsOver = function(event, o) {
if ((!o) || o==null) return false;
var pos = o.offset();
var ex = event.pageX;
var ey = event.pageY;
if (
ex>=pos.left
&& ex<=pos.left+o.width()
&& ey>=pos.top
&& ey<=pos.top+o.height()
) {
return true;
}
return false;
};
I use this function to check that the mouse really leaved when I received the mouseout event :
$('body').delegate(' myselector ', 'mouseenter', function(event) {
bubbling.bubbleTarget = $(this);
// store somewhere that the mouse is in the object
}).live('mouseout', function(event) {
if (bubbling.eventIsOver(event, bubbling.bubbleTarget)) return;
// store somewhere that the mouse leaved the object
});

You can use variablename = setInterval(...) to initiate a function repeatedly on mouseover, and clearInterval(variablename) to stop it on mouseout.
http://jsfiddle.net/XE8sK/
var marker;
$('#test').on('mouseover', function() {
marker = setInterval(function() {
$('#siren').show().fadeOut('slow');
}, 500);
}).on('mouseout', function() {
clearInterval(marker);
});​

jQuery has the hover() method which gives you this functionality out of the box:
$('.myiv').hover(
function () {
// the element is hovered over... do stuff
},
function () {
// the element is no longer hovered... do stuff
}
);
To check every x milliseconds if the element is still hovered and respond adjust to the following:
var x = 10; // number of milliseconds
var intervalId;
$('.myiv').hover(
function () {
// the element is hovered over... do stuff
intervalId = window.setInterval(someFunction, x);
},
function () {
// the element is no longer hovered... do stuff
window.clearInterval(intervalId);
}
);
DEMO - http://jsfiddle.net/z8yaB/

var interval = 0;
$('.myiv').hover(
function () {
interval = setInterval(function(){
console.log('still hovering');
},1000);
},
function () {
clearInterval(interval);
}
);

Trying to get my slideshow plugin to infinitely loop (by going back to the first state)

I wrote a slideshow plugin, but for some reason maybe because I've been working on it all day, I can't figure out exactly how to get it to go back to state one, once it's reached the very last state when it's on auto mode.
I'm thinking it's an architectual issue at this point, because basically I'm attaching the amount to scroll left to (negatively) for each panel (a panel contains 4 images which is what is currently shown to the user). The first tab should get: 0, the second 680, the third, 1360, etc. This is just done by calculating the width of the 4 images plus the padding.
I have it on a setTimeout(function(){}) currently to automatically move it which works pretty well (unless you also click tabs, but that's another issue). I just want to make it so when it's at the last state (numTabs - 1), to animate and move its state back to the first one.
Code:
(function($) {
var methods = {
init: function(options) {
var settings = $.extend({
'speed': '1000',
'interval': '1000',
'auto': 'on'
}, options);
return this.each(function() {
var $wrapper = $(this);
var $sliderContainer = $wrapper.find('.js-slider-container');
$sliderContainer.hide().fadeIn();
var $tabs = $wrapper.find('.js-slider-tabs li a');
var numTabs = $tabs.size();
var innerWidth = $wrapper.find('.js-slider-container').width();
var $elements = $wrapper.find('.js-slider-container a');
var $firstElement = $elements.first();
var containerHeight = $firstElement.height();
$sliderContainer.height(containerHeight);
// Loop through each list element in `.js-slider-tabs` and add the
// distance to move for each "panel". A panel in this example is 4 images
$tabs.each(function(i) {
// Set amount to scroll for each tab
if (i === 1) {
$(this).attr('data-to-move', innerWidth + 20); // 20 is the padding between elements
} else {
$(this).attr('data-to-move', innerWidth * (i) + (i * 20));
}
});
// If they hovered on the panel, add paused to the data attribute
$('.js-slider-container').hover(function() {
$sliderContainer.attr('data-paused', true);
}, function() {
$sliderContainer.attr('data-paused', false);
});
// Start the auto slide
if (settings.auto === 'on') {
methods.auto($tabs, settings, $sliderContainer);
}
$tabs.click(function() {
var $tab = $(this);
var $panelNum = $(this).attr('data-slider-panel');
var $amountToMove = $(this).attr('data-to-move');
// Remove the active class of the `li` if it contains it
$tabs.each(function() {
var $tab = $(this);
if ($tab.parent().hasClass('active')) {
$tab.parent().removeClass('active');
}
});
// Add active state to current tab
$tab.parent().addClass('active');
// Animate to panel position
methods.animate($amountToMove, settings);
return false;
});
});
},
auto: function($tabs, settings, $sliderContainer) {
$tabs.each(function(i) {
var $amountToMove = $(this).attr('data-to-move');
setTimeout(function() {
methods.animate($amountToMove, settings, i, $sliderContainer);
}, i * settings.interval);
});
},
animate: function($amountToMove, settings, i, $sliderContainer) {
// Animate
$('.js-slider-tabs li').eq(i - 1).removeClass('active');
$('.js-slider-tabs li').eq(i).addClass('active');
$('#js-to-move').animate({
'left': -$amountToMove
}, settings.speed, 'linear', function() {});
}
};
$.fn.slider = function(method) {
if (methods[method]) {
return methods[method].apply(this, Array.prototype.slice.call(arguments, 1));
} else if (typeof method === 'object' || !method) {
return methods.init.apply(this, arguments);
} else {
return false;
}
};
})(jQuery);
$(window).ready(function() {
$('.js-slider').slider({
'speed': '10000',
'interval': '10000',
'auto': 'on'
});
});​
The auto and animate methods are where the magic happens. The parameters speed is how fast it's animated and interval is how often, currently set at 10 seconds.
Can anyone help me figure out how to get this to "infinitely loop", if you will?
Here is a JSFiddle

It would probably be better to let go of the .each() and setTimeout() combo and use just setInterval() instead. Using .each() naturally limits your loop to the length of your collection, so it's better to use a looping mechanism that's not, and that you can break at any point you choose.
Besides, you can readily identify the current visible element by just checking for .active, from what I can see.
You'd probably need something like this:
setInterval(function () {
// do this check here.
// it saves you a function call and having to pass in $sliderContainer
if ($sliderContainer.attr('data-paused') === 'true') { return; }
// you really need to just pass in the settings object.
// the current element you can identify (as mentioned),
// and $amountToMove is derivable from that.
methods.animate(settings);
}, i * settings.interval);
// ...
// cache your slider tabs outside of the function
// and just form a closure on that to speed up your manips
var slidertabs = $('.js-slider-tabs');
animate : function (settings) {
// identify the current tab
var current = slidertabs.find('li.active'),
// and then do some magic to determine the next element in the loop
next = current.next().length >= 0 ?
current.next() :
slidertabs.find('li:eq(0)')
;
current.removeClass('active');
next.addClass('active');
// do your stuff
};
The code is not optimized, but I hope you see where I'm getting at here.

Javascript "while hovered" loop

Can anybody help me on this one...I have a button which when is hovered, triggers an action. But I'd like it to repeat it for as long as the button is hovered.
I'd appreciate any solution, be it in jquery or pure javascript - here is how my code looks at this moment (in jquery):
var scrollingposition = 0;
$('#button').hover(function(){
++scrollingposition;
$('#object').css("right", scrollingposition);
});
Now how can i put this into some kind of while loop, so that #object is moving px by px for as #button is hovered, not just when the mouse enters it?

OK... another stab at the answer:
$('myselector').each(function () {
var hovered = false;
var loop = window.setInterval(function () {
if (hovered) {
// ...
}
}, 250);
$(this).hover(
function () {
hovered = true;
},
function () {
hovered = false;
}
);
});
The 250 means the task repeats every quarter of a second. You can decrease this number to make it faster or increase it to make it slower.

Nathan's answer is a good start, but you should also use window.clearInterval when the mouse leaves the element (mouseleave event) to cancel the repeated action which was set up using setInterval(), because this way the "loop" is running only when the mouse pointer enters the element (mouseover event).
Here is a sample code:
function doSomethingRepeatedly(){
// do this repeatedly when hovering the element
}
var intervalId;
$(document).ready(function () {
$('#myelement').hover(function () {
var intervalDelay = 10;
// call doSomethingRepeatedly() function repeatedly with 10ms delay between the function calls
intervalId = setInterval(doSomethingRepeatedly, intervalDelay);
}, function () {
// cancel calling doSomethingRepeatedly() function repeatedly
clearInterval(intervalId);
});
});
I created a sample code on jsFiddle which demonstrates how to scroll the background-image of an element left-to-right and then backwards on hover with the code shown above:
http://jsfiddle.net/Sk8erPeter/HLT3J/15/

If its an animation you can "stop" an animation half way through. So it looks like you're moving something to the left so you could do:
var maxScroll = 9999;
$('#button').hover(
function(){ $('#object').animate({ "right":maxScroll+"px" }, 10000); },
function(){ $('#object').stop(); } );

var buttonHovered = false;
$('#button').hover(function () {
buttonHovered = true;
while (buttonHovered) {
...
}
},
function () {
buttonHovered = false;
});
If you want to do this for multiple objects, it might be better to make it a bit more object oriented than a global variable though.
Edit:
Think the best way of dealing with multiple objects is to put it in an .each() block:
$('myselector').each(function () {
var hovered = false;
$(this).hover(function () {
hovered = true;
while (hovered) {
...
}
},
function () {
hovered = false;
});
});
Edit2:
Or you could do it by adding a class:
$('selector').hover(function () {
$(this).addClass('hovered');
while ($(this).hasClass('hovered')) {
...
}
}, function () {
$(this).removeClass('hovered');
});

var scrollingposition = 0;
$('#button').hover(function(){
var $this = $(this);
var $obj = $("#object");
while ( $this.is(":hover") ) {
scrollingposition += 1;
$obj.css("right", scrollingposition);
}
});