function calcCubicFeet() {
	
	if ( (document.frmCalc1.postdiameter.value.length != 0) && (document.frmCalc1.postdepth.value.length != 0) ) {
		var postradius = document.frmCalc1.postdiameter.value / 2;
		var vcfph = 3.14159265 * (postradius * postradius) * document.frmCalc1.postdepth.value / 1728;
		var vpcyc = 27 / vcfph;
		document.frmCalc1.cfph.value = vcfph.toFixed(4); 
		document.frmCalc1.pcyc.value = vpcyc.toFixed(4); 
	} else {
		document.frmCalc1.cfph.value = "";
		document.frmCalc1.pcyc.value = "";
	}
	
}