function Left(str, n){
	if (n <= 0)
	    return "";
	else if (n > String(str).length)
	    return str;
	else
	    return String(str).substring(0,n);
}

function Right(str, n){
    if (n <= 0)
       return "";
    else if (n > String(str).length)
       return str;
    else {
       var iLen = String(str).length;
       return String(str).substring(iLen, iLen - n);
    }
}

function highlight(classed) {
	var control, thisclass, newclass;
	var message = ""
	for (var x=1;x<=19;x++) {
		control = document.getElementById('c'+x)
		if (control!=null) {
			thisclass = control.className;
			newclass = thisclass;
			if (classed=='') {
				if ((Right(thisclass,5)=="_dull")||(Right(thisclass,5)=="_high")) {
					newclass = Left(thisclass,String(thisclass).length-5);
				}
			} else {
				if (thisclass==classed) {
					newclass = thisclass+"_high";
				} else {
					newclass = thisclass+"_dull";
				}
			}
			control.className = newclass;
		}
		//message = message+"c"+x+" = "+newclass+"<br/>";
	}
	//document.getElementById("debug").innerHTML = message;
}