smartscroll
smartscroll is a tiny (1815b minfied + gzipped) jQuery plugin that has these independent features:
- Section scrolling - Scrolljacking
- Auto-hash - Updates the URL hash based on current position on page
- Responsive - You can disable scrolljacking below a set breakpoint
It also supports:
- Varied Section Heights
- Hybrid Scrolling - Both normal and scrolljacking on the same page
- Compatible with scrollbar - Can use scrollbar as well as mousewheel
- Disabling permalink history
- Correctly detects scroll events for inertial scrolling, by integrating with lethargy as a soft dependency (which means it will work without it)
- Provides events you can listen to, by integrating with EventEmitter as a soft dependency
Demo
Requirements
- There can only be one set of adjoining sections
How to Use
Install lethargy, which is available as a Bower package, which you can install with bower install.
Structure your HTML like so (default options included)
<body> <div class="section-wrapper"> <div class="section" data-hash="section-hash-name"></div> <div class="section" data-hash="section-hash-name"></div> </div> <script src="path/to/lethargy.min.js"> <script src="https://rawgit.com/Olical/EventEmitter/master/EventEmitter.min.js"></script> <script src="path/to/smartscroll.min.js"> <script> var options = { mode: "vp", // "vp", "set" autoHash: false, sectionScroll: true, initialScroll: true, keepHistory: false, sectionWrapperSelector: ".section-wrapper", sectionClass: "section", animationSpeed: 300, headerHash: "header", breakpoint: null, eventEmitter: null, dynamicHeight: false }; $.smartscroll(options); </script> </body> You may also want to link to
styles.css, but all that does is to ensure thehtmlandbodyelements have no margins nor padding
You may also leave out lethargy, but smartscroll may not work as well with scroll devices that uses inertial scrolling. Performance with lethargy can be slower, but it will be improved with further development.
Options
mode- (String) Valid options are:vp(Viewport) - The sections will be automatically sized to be the same as the viewportset- Use the height and width set by CSS (use this for having different heights for different sections)
autoHash- (Boolean) Whether the auto-hashing feature is enabled. If you use this feature, it is important to use EventEmitter as well, otherwise smartscroll will listen to everyscrollevent, which is very resource-draining and can make the animation more 'glitchy'sectionScroll- (Boolean) Whether the section-scrolling feature is enabledinitialScroll- (Boolean) Whether smartscroll should scroll to the position specified by the hash on initial loadkeepHistory- (Boolean) Whether scrolling through different sections will be recorded in the browser's historysectionWrapperSelector- (String) The CSS selector for the block element which wraps around your sectionssectionClass- (String) The class name applied to each sectionanimationSpeed- (Integer) Time taken for the scroll animation, in milisecondsheaderHash- (String) The hash for the section above the sections, must be non-empty to reliably ensure the page do not jump when updating the hash value across browsers (as#means_top)breakpoint- (Integer) The width of the browser below which scrolljacking will be disabledsectionSelector- (String) The selector applied to each section, overridessectionClassand allow more flexibility in choosing a selector. (Added in 2.1.0)dynamicHeight- (Boolean) If you are going to be dynamically adding and removing content so as to change the position and/or size of the section wrappers and/or sections, then set this to true. Set to false otherwise to increase performance.eventEmitter- (Object) If you pass in an EventEmitter object, autoHashing will be much more efficient. You can also listen to the scroll events this way. Defaults tonull.ie8- If you need to support Internet Explorer 8, change this totrue. Defaults tofalse.bindSwipe- (Boolean) Allow for listening of swipe events. Requires EventEmitter. Defaults totruebindKeyboard- (Boolean) Allow for keyboard events (up and down arrows) to control slides. Defaults totrue
Events
Smartscroll has a soft dependency on EventEmitter. If present, smartscroll can provide six events scrollStart, scrollEnd, swipeLeft, swipeRight, swipeDown and swipeUp. The scrollStart and scrollEnd listener will receive the slide number as its only argument; the first slide will have a number of 1, the section before the sectionWrapper will have a number of 0.
var ee = new EventEmitter(); var scrollStartListener = function (slideNumber) { console.log("Scrolling to " + slideNumber); } var scrollEndListener = function () { console.log("Scrolling End"); } ee.addListener('scrollStart', scrollStartListener); ee.addListener('scrollEnd', scrollEndListener); $.smartscroll({ ... eventEmitter: ee }); The other listeners receive no arguments.
var ee = new EventEmitter(); var swipeUpListener = function () { console.log("Swiping Up"); } var swipeDownListener = function () { console.log("Swiping Down"); } $.smartscroll({ ... eventEmitter: ee, bindSwipe: true }); ee.addListener('swipeUp', swipeUpListener); ee.addListener('swipeDown', swipeDownListener); Manual Scroll
You can manually scroll up or scroll down.
When you first initiate smartscroll with $.smartscroll(), it returns an object. In that object is the scroll function, which is called with a single parameter. If the parameter is truthy, it will scroll down, otherwise, it will scroll up.
var smartscroll = $.smartscroll(); smartscroll.scroll(1); Architecture
Currently, there are two features of smartscroll, and this is how it's implemented:
- Smooth scroll by section
The mousewheel and DOMMouseScroll (for Firefox) events are bound.
When such event is fired in vp mode, smartscroll will find it's most prominent section (one which occupies most of the screen), and smoothly scroll to the section above or below it.
When the event is fired in set mode, smartscroll will find which section occupies the middle of the screen, and smoothly scroll to the section above or below it.
When scrolling outside of the sections, normal scrolling resumes.
- Changing URL hash based on the current section
The scroll event is bound.
When the event is fired in vp mode, smartscroll will see which section occupies the top of the viewport, and if the hash is different, replace it with the new one.
When the event is fired in set mode, smartscroll will see which section occupies the middle of the viewport, and if the hash is different, replace it with the new one.
