$$('a.AjaxContentsLoader').invoke('observe','click',this.respondToClick);
function respondToClick(event){
    var url=this.readAttribute('link');
    getPage(url);
    function getPage(url){
        $('Contents').hide();
        new Effect.Appear('ContentsLoader',{duration:0.1});
        var myAjax=new Ajax.Updater('Contents',url,{
            method:'post',
            onSuccess:Success
        });
        return;
    };
    
    function Success(){
        new Effect.Fade('ContentsLoader',{duration:0.7});
        new Effect.Appear('Contents',{duration:0.7,queue:'end'})
    };
};