$('Contents').hide();
new Effect.Appear('ContentsLoader',{duration:0.1});
var myAjax=new Ajax.Updater('Contents','pages/home.php',{
    method:'post',
    onSuccess:Success}
);
function Success(){
    new Effect.Fade('ContentsLoader',{duration:0.7});
    new Effect.Appear('Contents',{duration:0.7,queue:'end'})
};