tickets/app/assets/javascripts/jquery.viewport.js

58 lines
1.9 KiB
JavaScript

/*
* Viewport - jQuery selectors for finding elements in viewport
*
* Copyright (c) 2008-2009 Mika Tuupola
*
* Licensed under the MIT license:
* http://www.opensource.org/licenses/mit-license.php
*
* Project home:
* http://www.appelsiini.net/projects/viewport
*
*/
(function($) {
$.belowthefold = function(element, settings) {
var fold = $(window).height() + $(window).scrollTop();
return fold <= $(element).offset().top - settings.threshold;
};
$.abovethetop = function(element, settings) {
var top = $(window).scrollTop();
return top >= $(element).offset().top + $(element).height() - settings.threshold;
};
$.rightofscreen = function(element, settings) {
var fold = $(window).width() + $(window).scrollLeft();
return fold <= $(element).offset().left - settings.threshold;
};
$.leftofscreen = function(element, settings) {
var left = $(window).scrollLeft();
return left >= $(element).offset().left + $(element).width() - settings.threshold;
};
$.inviewport = function(element, settings) {
return !$.rightofscreen(element, settings) && !$.leftofscreen(element, settings) && !$.belowthefold(element, settings) && !$.abovethetop(element, settings);
};
$.extend($.expr[':'], {
"below-the-fold": function(a, i, m) {
return $.belowthefold(a, {threshold : 0});
},
"above-the-top": function(a, i, m) {
return $.abovethetop(a, {threshold : 0});
},
"left-of-screen": function(a, i, m) {
return $.leftofscreen(a, {threshold : 0});
},
"right-of-screen": function(a, i, m) {
return $.rightofscreen(a, {threshold : 0});
},
"in-viewport": function(a, i, m) {
return $.inviewport(a, {threshold : 0});
}
});
})(jQuery);