// This function unchecks the all checkbox if one or more other checkboxes are set
		// unchek other checkboyes if the all checkbox is set
		// c is the checked box object
	  function check(c) {
			if (c.name != "D0") {
			  cc = document.getElementById("D0");
				cc.checked = false;
			} else {
			  // 'i' goes from 1 to the max checkbox's name (if you add one checkbox, increase the
				// X value (eg: (i=1; i<=X; i++)) in the line below...
			  for (i=1; i<=18; i++) {
				  cc = document.getElementById("D"+i);
				  cc.checked = false;
				}
			}
		}