openDiv = function(divpre,divnum) {
	if (divpre == 'bc') {
		document.getElementById('sc-'+divnum).style.display = 'none';
		document.getElementById('bc-'+divnum).style.display = 'block';
	}
	else if (divpre == 'sc') {
		document.getElementById('bc-'+divnum).style.display = 'none';
		document.getElementById('sc-'+divnum).style.display = 'block';
	}
  }