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visibilityChanged.js
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visibilityChanged.js
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/**
* Visible State Change for DOM Elements
* https://iprodev.github.io/jquery.visibilityState/
*
* Copyright (c) 2017 iProDev
* Licensed under the MIT license.
*/
(function ($) {
var namespace = 'visibilityState',
visibleEvent = 'visible',
hiddenEvent = 'hidden',
elements = [],
length = 0,
l = 0,
exist, item, isVisibile, timeID;
/*
Function
Function ( )
Return Type:
Void
Description:
Checks elements visibility status and call the events and callbacks.
*/
var checkVisibility = function () {
if (length === 0)
return;
l = length;
while(l--) {
item = elements[l];
isVisibile = item.$element.is(':visible');
if (isVisibile !== item.isVisibile) {
if (item.event) {
if (item.event === visibleEvent && isVisibile)
item.$element.triggerHandler(visibleEvent);
else if (item.event === hiddenEvent && !isVisibile)
item.$element.triggerHandler(hiddenEvent);
}
else
item.fn.call(item.$element[0], isVisibile);
}
elements[l].isVisibile = isVisibile;
}
};
/*
Function
Function ( $element: jQuery DOM Object, fn: Function, event: String )
Return Type:
Boolean
Description:
Add element to visibility elements check list.
*/
var addElement = function ($element, fn, event) {
if (checkElement($element, fn, event) === false) {
// Push element to visibility elements check list
elements.push({
$element: $element,
fn: fn,
isVisibile: null,
event: event
});
// Calculate the length
length = elements.length;
// Refresh the interval timer
clearInterval(timeID);
timeID = setInterval(checkVisibility, 100);
return true;
}
return false;
};
/*
Function
Function ( $element: jQuery DOM Object, fn: Function, event: String )
Return Type:
Boolean
Description:
Remove element from visibility elements check list.
*/
var removeElement = function ($element, fn, event) {
var index = checkElement($element, fn, event);
if (index !== false) {
// Remove element from visibility elements check list
elements.splice(index, 1);
// Calculate the length
length = elements.length;
return true;
}
return index;
};
/*
Function
Function ( $element: jQuery DOM Object, fn: Function, event: String )
Return Type:
Boolean|Integer
Description:
Check is element exists in visibility elements check list.
*/
var checkElement = function ($element, fn, event) {
exist = false;
l = length;
while(l--) {
item = elements[l];
if ($element[0] === item.$element[0] && fn === item.fn && event === item.event) {
exist = l;
break;
}
}
return exist;
};
// Begin the plugin
$.fn[namespace] = function (fn) {
return this.each(function () {
addElement($(this), fn);
});
};
// Begin the visible special event
$.event.special[visibleEvent] = {
add: function(handleObj) {
var elem = this;
addElement($(this), handleObj.handler, visibleEvent);
},
remove: function(handleObj) {
removeElement($(this), handleObj.handler, visibleEvent);
}
};
// Begin the visible special event
$.event.special[hiddenEvent] = {
add: function(handleObj) {
addElement($(this), handleObj.handler, hiddenEvent);
},
remove: function(handleObj) {
removeElement($(this), handleObj.handler, hiddenEvent);
}
};
})(jQuery);