http://acroniscoupon.info/js/jquery.appear0d09.js

1/*
2 * jQuery.appear
3 * http://code.google.com/p/jquery-appear/
4 *
5 * Copyright (c) 2009 Michael Hixson
6 * Licensed under the MIT license (http://www.opensource.org/licenses/mit-license.php)
7 */
8(function ($) {
9  $.fn.appear = function (f, o) {
10    var s = $.extend({ one: true }, o);
11    return this.each(function () {
12      var t = $(this);
13      t.appeared = false;
14      if (!f) {
15        t.trigger("appear", s.data);
16        return;
17      }
18      var w = $(window);
19      var c = function () {
20        if (!t.is(":visible")) {
21          t.appeared = false;
22          return;
23        }
24        var a = w.scrollLeft();
25        var b = w.scrollTop();
26        var o = t.offset();
27        var x = o.left;
28        var y = o.top;
29        if (
30          y + t.height() >= b &&
31          y <= b + w.height() &&
32          x + t.width() >= a &&
33          x <= a + w.width()
34        ) {
35          if (!t.appeared) t.trigger("appear", s.data);
36        } else {
37          t.appeared = false;
38        }
39      };
40      var m = function () {
41        t.appeared = true;
42        if (s.one) {
43          w.unbind("scroll", c);
44          var i = $.inArray(c, $.fn.appear.checks);
45          if (i >= 0) $.fn.appear.checks.splice(i, 1);
46        }
47        f.apply(this, arguments);
48      };
49      if (s.one) t.one("appear", s.data, m);
50      else t.bind("appear", s.data, m);
51      w.scroll(c);
52      $.fn.appear.checks.push(c);
53      c();
54    });
55  };
56  $.extend($.fn.appear, {
57    checks: [],
58    timeout: null,
59    checkAll: function() {
60		var length = $.fn.appear.checks.length;
61		if (length > 0) {
62			while (length--) {
63				try {
64					($.fn.appear.checks[length])();
65				} catch (e) {}
66			}
67		}
68	}, 
69    run: function () {
70      if ($.fn.appear.timeout) clearTimeout($.fn.appear.timeout);
71      $.fn.appear.timeout = setTimeout($.fn.appear.checkAll, 20);
72    },
73  });
74  $.each(
75    [
76      "append",
77      "prepend",
78      "after",
79      "before",
80      "attr",
81      "removeAttr",
82      "addClass",
83      "removeClass",
84      "toggleClass",
85      "remove",
86      "css",
87      "show",
88      "hide",
89    ],
90    function (i, n) {
91      var u = $.fn[n];
92      if (u) {
93        $.fn[n] = function () {
94          var r = u.apply(this, arguments);
95          $.fn.appear.run();
96          return r;
97        };
98      }
99    }
100  );
101})(jQuery);