function bgChange(th,st){
	tdid = th.id;
	tdlen = document.getElementsByClassName(tdid).length;
	if( st == 'on'){
		for(i=0; i<tdlen; i++){
			document.getElementsByClassName(tdid)[i].style.backgroundColor = '#fcfaf2';
		}
	} else if( st == 'off' ) {
		for(i=0; i<tdlen; i++){
			document.getElementsByClassName(tdid)[i].style.backgroundColor = '#ffffff';
		}
	}
}