// Browser safe opacity handling function
function setOpacity(value, id) {
 document.getElementById('popup' + id).style.opacity = value / 10;
 document.getElementById('popup' + id).style.filter = 'alpha(opacity=' + value * 10 + ')';
}

function fadeInMyPopup(id) {
 for( var i = 0 ; i <= 100 ; i++ )
   setTimeout( 'setOpacity(' + (i / 10) + ', ' + id + ')', 8 * i );
}

function fadeOutMyPopup(id) {
 for( var i = 0 ; i <= 100 ; i++ ) {
   setTimeout( 'setOpacity(' + (10 - i / 10) + ', ' + id +  ')' , 8 * i );
 }

 setTimeout('closeMyPopup(' + id + ')', 800 );
}

function closeMyPopup(id) {
 document.getElementById('popup' + id).style.display = "none"
}

function fireMyPopup(id) {
 setOpacity(0, id);
 document.getElementById('popup' + id).style.display = "block";
 fadeInMyPopup(id);
}