function doit(){
	var amt=1*document.getElementById('c1amount').value+1*document.getElementById('c1fee').value;
	var rate=Math.pow(1+0.01*document.getElementById('c1rate').value,1/12);
	var period=document.getElementById('c1period').value;
	var delay=document.getElementById('c1delay').value;
	if (isFinite(amt+rate+period+delay)){
		var m1=0;
		var m2=amt*Math.pow(rate,delay);
		var m3;
		var eps=0.01;
		while(1){
			m3=(m1+m2)/2;
			z=amt*Math.pow(rate,delay-1);
			for(var i=1;i<=period;i++){
				z*=rate;
				z-=m3;
				if (z<0) {
					z=-1;
					break
				};
			};
			if (z<-eps)
				m2=m3
			else if (z>eps)
				m1=m3
			else
				break;
			if (Math.abs(m2-m1)<eps) break;			
		}
		document.getElementById('c1monthly').value=m3.toFixed(2)
	} else {
		document.getElementById('c1monthly').value='----';
	}
	setTimeout("doit();", 10);
}
doit();