function calculatetime(form) {
								//  get conversion factors from selected options
								var i = form.distunits.selectedIndex;
								var distunitsvalue = form.distunits.options[i].value; 
								var j = form.speedunits.selectedIndex;
								var speedunitsvalue = form.speedunits.options[j].value;
								//  calculate time in seconds    
								form.secondvalue.value = (form.distvalue.value * distunitsvalue) / (form.speedvalue.value * speedunitsvalue);
								//  convert to hours, minutes, seconds    
								form.hourvalue.value = parseInt(form.secondvalue.value / 3600);
								form.secondvalue.value = form.secondvalue.value - (form.hourvalue.value * 3600);
								form.minutevalue.value = parseInt(form.secondvalue.value / 60);
								form.secondvalue.value = parseInt(form.secondvalue.value - (form.minutevalue.value * 60));
								return true;
}
function calculatedistance(form) {
									//  get conversion factors from selected options
									var i = form.distunits.selectedIndex;
									var distunitsvalue = form.distunits.options[i].value; 
									var j = form.speedunits.selectedIndex;
									var speedunitsvalue = form.speedunits.options[j].value;
									//  convert time to seconds
									var temp = ((parseFloat(form.hourvalue.value) * 3600) + (parseFloat(form.minutevalue.value) * 60) + parseFloat(form.secondvalue.value));
									//  calculated distance
									form.distvalue.value = ((form.speedvalue.value * speedunitsvalue) * temp) / distunitsvalue; 
									return true;
}
function calculatespeed(form) {
								//  get conversion factors from selected options
								var i = form.distunits.selectedIndex;
								var distunitsvalue = form.distunits.options[i].value; 
								var j = form.speedunits.selectedIndex;
								var speedunitsvalue = form.speedunits.options[j].value;
								//  convert time to seconds
								var temp = ((parseFloat(form.hourvalue.value) * 3600) + (parseFloat(form.minutevalue.value) * 60) + parseFloat(form.secondvalue.value));
								//  calculate speed
								form.speedvalue.value = ((form.distvalue.value * distunitsvalue)  / (temp * speedunitsvalue)); 
								return true;
}
function clearcell(cell) {
							cell.value = "";
							return true;
}
function calculatesomething(form) {
									var x = form.xvalue.value;
									var y = form.yvalue.value;
									var wynik = 0;
									x = parseFloat(x);
									y = parseFloat(y);
									wynik = ( 120 * x ) / y;
									form.wynik.value = wynik;
								//	A = (120 x X) / Y
}