Visi.js is a small library written on vanilla.js. It doesn't require any dependencies. Visi.js provides functionality to monitor when dom element is partially in a viewport It adds some methods to simplify your work with handling of such event.
Visi on jsfiddler (Watch console)
-
Remote
<script type="text/javascript" src="https://cdn.rawgit.com/hellfrom/visi/master/visi.min.js" ></script> -
npm
npm install visi -
bower
bower install visi
Event names
visible and hidden
Short api
- add
.add(domElements); //single or multiple dom elements
Short api
- add
.add(domElements); //single or multiple dom elements
- on
.on(eventName,function(changedElement,off){
//off() removes event listeners from fired element
});
- once (unregisters all events from fired element after first triggering)
.once(eventName,function(changedElement){
//...
});
- off
var visi = Visi.add(/*dom elements*/);
visi.off(); //remove all event listeners from selection
- getOff
var off = Visi.add(dom)
.on('visible',callback)
.getOff();
off(); //remove all listeners from selection
HTML
<div class = "p1"
id = "id1">
Lorem...
</div>
<br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/>
<div class = "p2"
id = "id2">
Lorem ipsum...
</div>
<br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/>
<div class = "p3 p1">
Lorem ipsum dolor...
</div>
JS
var visi = Visi.add(document.getElementById('id1'))
.on('visible',function(){
console.log('visible id1');
});
visi.off();
Add event to the same instance again
visi.on('visible',function(){
console.log('visible again');
});
Add event only once - after first triggering it will automatically unregister all event listeners
Visi.add(document.getElementById('id1')).once('hidden',function(element,off){
//off() is not necessary for this use case
//...
});
Listen if element becomes hidden every time with .on
Visi.add(document.querySelectorAll('.p1'))
.on('hidden',function(element,off){
console.log('hidden id1',element);
console.log(arguments);
//unregister listeners only for element which
//became hidden after some scrolling etc.
off();
});
Get unregisters
var off = Visi.add(document.getElementById('id1'))
.on('visible',function(){
console.log('visible id1');
}).getOff();
//remove all events from all dom elements for current selection
off();