How to Check if an Element is Visible in the Browser Viewport with JQuery?

JQuery Check if Element is Visible in Viewport: A Comprehensive Explanation

Determining whether an element is visible within the browser's viewport is a common task in frontend development. JQuery provides a convenient way to achieve this with the help of plugins or custom functions.

Using a Plugin

The JQuery visible plugin offers a straightforward way to check the visibility of an element. However, you may encounter difficulties in implementing it with the provided function. Here's an example that will work with the visible plugin:

$('#element').visible(function() {
  // This function will be executed when the element is visible
});

Developing a Custom Function

If you prefer not to use a plugin, you can create a custom function to check for visibility:

$.fn.isInViewport = function() {
  var elementTop = $(this).offset().top;
  var elementBottom = elementTop + $(this).outerHeight();

  var viewportTop = $(window).scrollTop();
  var viewportBottom = viewportTop + $(window).height();

  return elementBottom > viewportTop && elementTop < viewportBottom;
};

Example Usage

Once you have defined the isInViewport function, you can use it as follows:

$(window).on('resize scroll', function() {
  if ($('#element').isInViewport()) {
    // The element is visible
  } else {
    // The element is not visible
  }
});

Limitations

Note that this function only checks for vertical visibility. If you need to determine horizontal visibility as well, you can extend the function accordingly.

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