window.onload Vs Document Ready

Launching Code on Document Ready

To ensure that their code runs after the browser finishes loading the document, many JavaScript programmers wrap their code in an onload function:




window.onload = function() {

    alert( "welcome" );

}
Unfortunately, the code doesn't run until all images are finished downloading, including banner ads. To run code as soon as the document is ready to be manipulated, jQuery has a statement known as the ready event:


$( document ).ready(function() {

    // Your code here.

});
For example, inside the ready event, you can add a click handler to the link:


$( document ).ready(function() {

    $( "a" ).click(function( event ) {

        alert( "Thanks for visiting!" );

    });

});