//Canterbury Continuous Spouting Dropheight Calculator
//Excell original & formula supplied by Stephen & Darren Hickson
//Javascript conversion by Paul Webster for Vision Web Solutions, Christchurch, New Zealand 
//April 2006


//do the maths already
function calculate(){
	pitch_radians = parseFloat(dE.inp_pitch.value)*Math.PI/180;
	
	tan_pr=Math.tan(pitch_radians);
	
	cos_pr=Math.cos(pitch_radians);
	
	//calualte height for concrete tile
	out_concrete=((parseFloat(dE.inp_soffit.value)+10)*tan_pr) + (dE.con_fbh.value-((dE.con_ctp.value/cos_pr)-(dE.con_fbw.value*tan_pr))-(dE.con_truss.value/(cos_pr))-dE.con_gbs.value);
	//round and assign to form element
	dE.out_concrete.value = Math.round(out_concrete*10)/10;

	//calualte height for metal tile
	out_metal=((parseFloat(dE.inp_soffit.value)+10)*tan_pr) + (dE.con_fbh.value-((dE.con_mtp.value/cos_pr)-(dE.con_fbw.value*tan_pr))-(dE.con_truss.value/(cos_pr))-dE.con_gbs.value);
	//round and assign to form element
	dE.out_metal.value = Math.round(out_metal*10)/10;
}


//pageload intitiation function
function init(){
	dE = document.getElementById('dropheight_calc');
	//dE.inp_pitch.value = 0;
	//dE.inp_soffit.value = 0;
	//dE.out_concrete.value = 'out_concrete';
	//calculate();
}