LateLoader is a project mainly written in JavaScript, it's free.
Lazy loading class
LateLoader is fully extensible lazy loading
class.
Provides Lazy Loading for:
From tunable parameters:
VisibilityWatcher class
Then just create an Instance on the target element(s)
#JS
new LateLoader.Img($$('img'));
And for the less common ones:
#JS
new LateLoader.Ajax('myajaxzone');
(see documentation for full setup)
#JS
new LateLoader.Object('myflashcontainer');
(see documentation for full setup)