// 
function calculateIt(div_id){

	var pad_length = 0;
	var pad_width = 0;
	var pad_dia = 0;
	
	var surface_area = 0;
	var maxload = 0;
	var plate_size_square = 0;
	var plate_size_dia = 0;
	
	
	var pad_length = document.form.length.value;
	var pad_width = document.form.width.value;
	var pad_dia = document.form.diameter.value;
	
	if(pad_length != 0 && pad_width != 0 && pad_dia == 0)surface_area = pad_length * pad_width;
	if(pad_length == 0 && pad_width == 0 && pad_dia != 0)surface_area = 3.14 * ((pad_dia / 2) * (pad_dia / 2));
	if(surface_area != 0)maxload = surface_area * 1.5;
	
	
	if(surface_area != 0)plate_size_square = Math.sqrt(surface_area * 3);
	if(surface_area != 0)plate_size_dia = (Math.sqrt((surface_area * 3) / 3.14)) * 2;
	
	surface_area = (Math.round(surface_area * 10)) / 10;
	maxload = (Math.round(maxload * 10)) / 10;
	plate_size_square = (Math.round(plate_size_square * 10)) / 10;
	plate_size_dia = (Math.round(plate_size_dia * 10)) / 10;
		
	document.form.psa.value  = surface_area;
	document.form.maxload.value  = maxload;
	document.form.platesizesquare.value  = plate_size_square;
	document.form.platesizediameter.value  = plate_size_dia;
	document.getElementById(div_id).style.display = '';
	}
	
function resetIt(div_id){
	document.form.length.value = '';
	document.form.width.value = '';
	document.form.diameter.value = '';
	
	document.form.psa.value  = '';
	document.form.maxload.value  = '';
	document.form.platesizesquare.value  = '';
	document.form.platesizediameter.value  = '';
	document.getElementById(div_id).style.display = 'none';
}