function checkTariff ( form )
{

// Check for empties
var fu = form.fu.value;
var nu = form.nu.value;
var bp = form.bp.value;
var sc = document.owntariff.sc.checked;
if (!sc) {
  if (fu == "" || nu == "" || bp == "") {
    alert( "Please enter all Tariff values." );
    return false ;
  }
  } else {
  if (fu == "") {
    alert( "Please enter the Unit Price per KWh." );
    return false ;
  	}
  }

// Check they're numbers

if (isNaN(fu)) {
	alert( "'First Units' must be a number." );
    return false ;
}

if (isNaN(nu)) {
	alert( "'Next Units' must be a number." );
    return false ;
}

if (isNaN(bp)) {
	alert( "'Breakpoint' must be a number." );
    return false ;
	}
}

function checkSC () {
	var sc = document.owntariff.sc.checked;
	//alert (sc);
	if (sc) {
		togglerow('row_su');
		togglerow('row_bp');
		document.getElementById("txt_first").innerHTML="";
		document.getElementById("txt_fudesc").innerHTML="";
	}
	 else {
		togglerow('row_su');
		togglerow('row_bp');
		document.getElementById("txt_first").innerHTML="First ";
		document.getElementById("txt_fudesc").innerHTML="Usually the higher priced unit of electricity up to a given breakpoint.";
	}
	

}
 
function changetext(elemid, content) {
	document.getElementById(elemid).innerHTML=content; 
}

var textBlocks = new Array('pence','eurocents','cents');
function changeUnit(elemid) {
	var ind = document.getElementById(elemid).selectedIndex; 
	document.getElementById("txt_unit1").innerHTML=textBlocks[ind];
	document.getElementById("txt_unit2").innerHTML=textBlocks[ind];
} 

function togglerow(id) {
	body=document.getElementById(id);
	if (body.style.display == 'none') {
	try {
		body.style.display='table-row';
		} catch(e) {
		body.style.display = 'block';
		}
		}
		else {
		body.style.display = 'none';
		}
}

function toggleDetail(id,number) {
	for (i=1;i<=number;i++) {
		body=document.getElementById(id+i);
		if (body) {
			if (body.style.display == 'none') {
            	try {
					body.style.display='table-row';
					} catch(e) {
					body.style.display = 'block';
					}
				}
				else {
					body.style.display = 'none';
				}
			}
		}
	}