[jQuery] how to do some animation when the page loads?

when the DOM is ready you can write

$(document).ready(function(){
$("#divname").hide();
});

Say now, you want to try and do some animation done by default, (in
the below example I have done some animation only when the user do
mouse over, how can i do that by default as in when the page loads)

$(document).ready(function(){
$(".divname").mouseover(function(){
$(".divname").animate({
         opacity: 0.5,
       }, 300 );
});
});