function converter() {
// THE FORM
var form=$('converter');

// SOURCE INPUT
var sourceinput=form['source'];
// EXTEND FOR IE BUG
var ie=Element.extend(sourceinput);
// GET VALUE
var source=ie.getValue();

// SOURCE TYPE
var sourcetypeselect=form['source_type'];
// EXTEND FOR IE BUG
var ie=Element.extend(sourcetypeselect);
// GET VALUE
var sourcetype=ie.getValue();

// CONVERTED TYPE
var convertedtypeselect=form['converted_type'];
// EXTEND FOR IE BUG
var ie=Element.extend(convertedtypeselect);
// GET VALUE
var convertedtype=ie.getValue();

// CONVERTED
var converted=form['converted'];


if(sourcetype=="Cubic Feet" && convertedtype=="Cubic Metres") { 
	var conversion=source*0.02831685;
	//round to 4 decimals
	var result=Math.round(conversion*10000)/10000;
	converted.value=result;
	}

else if (sourcetype=="Cubic Metres" && convertedtype=="Cubic Feet") { 
	var conversion=source*35.3146667;
	var result=Math.round(conversion*10000)/10000
	converted.value=result
	} 

else { 
	alert("This is not going to work. Please choose an other conversion type."); }
	}