How can I hide an element when the page is scrolled?

A basic directive would look like this. One key point is you’ll need to call scope.$apply() since scroll will run outside of the normal digest cycle.

app = angular.module('myApp', []);
app.directive("scroll", function ($window) {
    return function(scope, element, attrs) {
        angular.element($window).bind("scroll", function() {
            scope.visible = false;
            scope.$apply();
        });
    };
});

I found this jsfiddle which demonstrates it nicely http://jsfiddle.net/88TzF/