tiarno

// Given an iframe id and an anchor id that is present within the iframe,
// determine whether the element is visible/present inside the window viewport.
// This is not about the css 'display' property; this shows whether
// the window viewport contains the element. 

var isVisible = function (anchor, iframe_id) {
    var ifrId = iframe_id || 'bv_page';
    var ifrOffset = window.parent.document.getElementById(ifrId).offsetTop;
    var myloc = document.getElementById(anchor).offsetTop + ifrOffset;
    var viewtop = window.parent.scrollY;

paulirish

// http://paulirish.com/2011/requestanimationframe-for-smart-animating/
// http://my.opera.com/emoller/blog/2011/12/20/requestanimationframe-for-smart-er-animating

// requestAnimationFrame polyfill by Erik Möller. fixes from Paul Irish and Tino Zijdel

// MIT license

(function() {
    var lastTime = 0;
    var vendors = ['ms', 'moz', 'webkit', 'o'];