function procClick(btn) {
	var btnId = btn.id.split("_");
	var col = btnId[0];
	var row = btnId[1];
	var cols = new Array("c1","c2","c3","c4","c5","ab");
	var ii, curId, curBtn;
	
	for (ii in cols) {
		curId = cols[ii] + "_" + row;
		if (cols[ii] != col) {
			var curBtn = document.getElementById(curId);
			curBtn.checked = false;
		}
	}
}