function dayNo(y,m,d){
  return --m>=0 && m<12 && d>0 && d<29+(
           4*(y=y&3||!(y%25)&&y&15?0:1)+15662003>>m*2&3
         ) && m*31-(m>1?(1054267675>>m*3-6&7)-y:0)+d;
}

Date.prototype.dayNo = function(){ var y=this.getFullYear(), m=this.getMonth(); return m*31-(m>1?(1054267675>>m*3-6&7)-(y&3||!(y%25)&&y&15?0:1):0)+this.getDate(); };