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Detecting Visibility Changes with jQuery
When working with dynamic content, it becomes necessary to perform actions based on the visibility of specific elements. jQuery provides a way to attach event handlers that trigger when a div becomes visible.
Solution:
To achieve this, you can extend the existing jQuery .show() method and trigger events before and after the visibility change. Here's a custom extension code snippet:
jQuery(function($) { var _oldShow = $.fn.show; $.fn.show = function(speed, oldCallback) { return $(this).each(function() { var obj = $(this), newCallback = function() { if ($.isFunction(oldCallback)) { oldCallback.apply(obj); } obj.trigger('afterShow'); }; // Trigger beforeShow event obj.trigger('beforeShow'); // Call the original show method with the new callback _oldShow.apply(obj, [speed, newCallback]); }); } });
Usage:
To use the extended .show() method, you can bind events to the beforeShow and afterShow triggers. For example:
jQuery(function($) { $('#test') .bind('beforeShow', function() { alert('beforeShow'); }) .bind('afterShow', function() { alert('afterShow'); }) .show(1000, function() { alert('in show callback'); }) .show(); });
This code will trigger the beforeShow and afterShow events when the div with the ID test is shown and hidden, allowing you to execute custom code based on the visibility change.
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