Limitless - Responsive Web Application Kit by Eugene Kopyov

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ScrollSpy component

Scrollspy is a component that automatically updates Bootstrap navigation or list group components based on scroll position to indicate which link is currently active in the viewport. Scrollspy has a few requirements to function properly:

It must be used on a Bootstrap nav component or list group.
Scrollspy requires position: relative; on the element you’re spying on, usually the <body>.
When spying on elements other than the <body>, be sure to have a height set and overflow-y: scroll; applied.
Anchors (<a>) are required and must point to an element with that id.

Usage via Data Attributes

To easily add scrollspy behavior to your topbar navigation, add data-spy="scroll" to the element you want to spy on (most typically this would be the <body>). Then add the data-target attribute with the ID or class of the parent element of any Bootstrap .nav component.

Add CSS styles:

body {
	position: relative;
}

And add markup:

<body data-spy="scroll" data-target=".sidebar">
	[...]
	<div class="sidebar sidebar-default">
		<div class="sidebar-content">
			[...]
		</div>
	</div>
	[...]
</body>

Usage via JavaScript

After adding position: relative; in your CSS, call the scrollspy via JavaScript:

// Initialize
$('body').scrollspy({ target: '.sidebar' });

Scrollspy Methods

Scrollspy supports 2 methods: refresh - when using scrollspy in conjunction with adding or removing of elements from the DOM, you'll need to call the refresh method; dispose - destroys an element’s scrollspy.

// Refresh Scrollspy
$('[data-spy="scroll"]').each(function () {
	var $spy = $(this).scrollspy('refresh')
});

// Destroy Scrollspy
$('[data-spy="scroll"]').scrollspy('dispose');

Scrollspy Options

Options can be passed via data attributes or JavaScript. For data attributes, append the option name to data-, as in data-offset="".

Name	Type	Default	Description
offset	number	10	Pixels to offset from top when calculating position of scroll.

Scrollspy Events

Event Type	Description
`activate.bs.scrollspy`	This event fires whenever a new item becomes activated by the scrollspy.

Example code:

// When Scrollspy is activated
$('#myScrollspy').on('activate.bs.scrollspy', function () {
	// do something…
})

Sticky component

Sticky-kit provides an easy way to attach elements to the page when the user scrolls such that the element is always visible. Just call stick_in_parent on the elements you want to be stuck inside of their parent. Sticky elements “bottom out” so they never leave the container, no more worrying if a sticky element will accidentally cover your footer.

Example code:

// Initialize Sticky
$("#sticky_item").stick_in_parent();

// Initialize with options
$("#sticky_item").stick_in_parent(options);

Plugin options

You can pass a hash of options to configure how Sticky Kit works. The following options are accepted, each one is optional:

Option	Default value	Description
`parent`	closest parent	The element will be the parent of the sticky item. The dimensions of the parent control when the sticky element bottoms out. Can be a selector
`inner_scrolling`	`true`	Boolean to enable or disable the ability of the sticky element to scroll independently of the scrollbar when it’s taller than the viewport
`sticky_class`	`.is_stuck`	The name of the CSS class to apply to elements when they have become stuck
`offset_top`	N/A	Offsets the initial sticking position by of number of pixels, can be either negative or positive
`spacer`	own spacer	Either a selector to use for the spacer element, or `false` to disable the spacer. The selector is passed to closest, so you should nest the sticky element within the spacer
`bottoming`	`true`	Boolean to control whether elements bottom out
`recalc_every`	Never	Integer specifying that a recalc should automatically take place between that many ticks. A tick takes place on every scroll event

Plugin events

Various events are triggered from a sticky element when its state changes. They are:

Event	Description
`sticky_kit:stick`	Triggered when element becomes stuck
`sticky_kit:unstick`	Triggered when element becomes unstuck. (Note: an element is still considered stuck when it has bottomed out)
`sticky_kit:bottom`	Triggered when element bottoms out
`sticky_kit:unbottom`	Triggered when element is no longer bottomed out
`sticky_kit:recalc`	Trigger this event to cause all sticky elements to be recalculated
`sticky_kit:detach`	remove sticky kit and restore element to original position

Components - Scrollspy