Test in JQuery if an element is at the top of screen

Question

I have a div that is positioned about 100px from the top of the browser window. When the user scrolls down, I want the div to stay where it is

Answer 1

var distance = $('div').offset().top,
    $window = $(window);

$window.scroll(function() {
    if ( $window.scrollTop() >= distance ) {
        // Your div has reached the top
    }
});

P.S. For better performance, you should probably throttle the scroll event handler.
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