$(document).ready and $(window).load

jQuery offers two powerful methods to execute code and attach event handlers: $(document).ready and $(window).load. The document ready event executes already when the HTML-Document is loaded and the DOM is ready, even if all the graphics haven’t loaded yet. If you want to hook up your events for certain elements before the window loads, then $(document).ready is the right place.

$(document).ready(function() {
// executes when HTML-Document is loaded and DOM is ready
alert("document is ready");
});

The window load event executes a bit later when the complete page is fully loaded, including all frames, objects and images. Therefore functions which concern images or other page contents should be placed in the load event for the window or the content tag itself.

$(window).load(function() {
// executes when complete page is fully loaded, including all frames, objects and images
alert("window is loaded");
});