function show (id) { 
whichdiv = document.getElementById(id);
	if (whichdiv.className=="hidden") { 
		whichdiv.className="shown";
	}
	else {
   		whichdiv.className="hidden";
	}
}

function expand (id) { 
whichrow = document.getElementById(id); 
   if (whichrow.className=="hidden") { 
      whichrow.className="shown"; 
   } 
}

function collapse (id) { 
   whichrow = document.getElementById(id); 
   if (whichrow.className=="shown") { 
      whichrow.className="hidden"; 
   } 
}

function MM_openBrWindow(theURL,winName,features) {
  window.open(theURL,winName,features);
}

function swapUnitsVisible() {
if (document.form.unit.value == "feet")
	{
	div_feet.style.display='inline';
	div_metres.style.display='none';
	}
if (document.form.unit.value == "metres")
	{
	div_feet.style.display='none';
	div_metres.style.display='inline';
	}
}