How to Auto Popup a CSS3 Modal Window When Page Loads?

Question

i am trying to figure this out.How o i make it work on page Load.

my css

.modalDialog {
    position: fixed;
    font-family: Arial, Helvetica, sans-         


        

Answer 1

set a div

        text here...

at style set display:hidden

#popup
{
    position:absolute;
    display:none;
    top:200px;
    left:50%;
    width:500px; 
    margin-left:-250px;
    border:1px solid blue; 
    padding:20px;
    background-color:white;
}

when page is loaded just set display:block