jQuery trigger action when a user scrolls past a certain part of the page

Hey all, I need a jQuery action to fire when a user scrolls past certain locations on the page. Is this even possible with jQuery? I have looked at .scroll in the jQuery API and I don't think this is what I need. It fires every time the user scrolls, but I need it to fire just when a user passes a certain area.

Solution 1:

Use the jquery event .scroll()

$(window).on('scroll', function() {
    var y_scroll_pos = window.pageYOffset;
    var scroll_pos_test = 150;             // set to whatever you want it to be

    if(y_scroll_pos > scroll_pos_test) {
        //do stuff
    }
});

http://jsfiddle.net/babumxx/hpXL4/

Solution 2:

Waypoints in jQuery should do it: http://imakewebthings.github.com/jquery-waypoints/

$('#my-el').waypoint(function(direction) {
  console.log('Reached ' + this.element.id + ' from ' + direction + ' direction.');
});

jQuery waypoints plugin documentation: http://imakewebthings.com/waypoints/guides/jquery-zepto/