function calculate(){
	var focallength = document.getElementById('focallength');
	var diameter = document.getElementById('diameter');
	var cameraaperture = document.getElementById('cameraaperture');
	var cameraiso = document.getElementById('cameraiso');
	var pinholeiso = document.getElementById('pinholeiso');
	var cameratiming = document.getElementById('cameratiming');
	if(focallength.value == "")
		alert("Please enter a value for 'Focal Length'")
	else if(diameter.value == "")
		alert("Please enter a value for 'Pinhole Diameter'")
	else
		document.getElementById('pinholeaperture').innerHTML = ' = f/' + (focallength.value - (focallength.value % diameter.value)) / diameter.value;
	if(cameraaperture.value == "")
		alert("Please enter a value for 'Camera Aperture'")
	else if(focallength.value == "")
		document.getElementById('exposurefactor').innerHTML = ' <a id="smaller">cannot be calculated without Focal Length</a>';
	else if(diameter.value == "")
		document.getElementById('exposurefactor').innerHTML = ' <a id="smaller">cannot be calculated without Pinhole Diameter</a>';
	else if(pinholeiso.value == "")
		document.getElementById('exposurefactor').innerHTML = ' = ' + (((focallength.value - (focallength.value % diameter.value)) / diameter.value) * ((focallength.value - (focallength.value % diameter.value)) / diameter.value)) / ((1 / 2) * cameraaperture.value * cameraaperture.value) + '<br><a id="smaller">More Accurate With ISO Compensation</a>';
	else if(cameraiso.value == "")
		document.getElementById('exposurefactor').innerHTML = ' = ' + (((focallength.value - (focallength.value % diameter.value)) / diameter.value) * ((focallength.value - (focallength.value % diameter.value)) / diameter.value)) / ((1 / 2) * cameraaperture.value * cameraaperture.value) + '<br><a id="smaller">More Accurate With ISO Compensation</a>';
	else
		document.getElementById('exposurefactor').innerHTML = ' = ' + ((((focallength.value - (focallength.value % diameter.value)) / diameter.value) * ((focallength.value - (focallength.value % diameter.value)) * cameraiso.value) / diameter.value)) / ((cameraaperture.value * cameraaperture.value) * pinholeiso.value);
	if(shutterspeed1.value == "")
		alert("Please enter a value for 'Shutter Speed'")
	else if(shutterspeed2.value == "")
		alert("Please enter a value for 'Shutter Speed'")
	else if(focallength.value == "")
		document.getElementById('pinholetiming').innerHTML = ' <a id="smaller">cannot be calculated without Focal Length</a>';
	else if(diameter.value == "")
		document.getElementById('pinholetiming').innerHTML = ' <a id="smaller">cannot be calculated without Pinhole Diameter</a>';
	else if(cameraaperture.value == "")
		document.getElementById('pinholetiming').innerHTML = ' <a id="smaller">cannot be calculated without Camera Aperture</a>';
	else if(pinholeiso.value == "")
		document.getElementById('pinholetiming').innerHTML = ' = ' + ((((focallength.value - (focallength.value % diameter.value)) / diameter.value) * ((focallength.value - (focallength.value % diameter.value)) / diameter.value)) / ((1 / 2) * cameraaperture.value * cameraaperture.value) * (shutterspeed1.value / shutterspeed2.value)) + '<a>secs</a><br><a id="smaller">More Accurate With ISO Compensation</a>';
	else if(cameraiso.value == "")
		document.getElementById('pinholetiming').innerHTML = ' = ' + ((((focallength.value - (focallength.value % diameter.value)) / diameter.value) * ((focallength.value - (focallength.value % diameter.value)) / diameter.value)) / ((1 / 2) * cameraaperture.value * cameraaperture.value) * (shutterspeed1.value / shutterspeed2.value)) + '<a>secs</a><br><a id="smaller">More Accurate With ISO Compensation</a>';
	else
		document.getElementById('pinholetiming').innerHTML = ' = ' + ( (((((focallength.value - (focallength.value % diameter.value)) / diameter.value) * ((focallength.value - (focallength.value % diameter.value)) * cameraiso.value) / diameter.value)) / ((cameraaperture.value * cameraaperture.value) * pinholeiso.value)) * (shutterspeed1.value / shutterspeed2.value) ) + 'secs';
	if(focallength.value == "")
		document.getElementById('pinholeaperture').innerHTML = ' <a id="smaller">cannot be calculated without Focal Length</a>';
	else if(diameter.value == "")
		document.getElementById('pinholeaperture').innerHTML = ' <a id="smaller">cannot be calculated without Pinhole Diameter</a>';
	else
		alert("Your Pinhole Timing has been calculated, Happy Snapping!")
}
function focallength(){
	alert("The 'Focal Length' is the distance in milimeters between the pinhole and the photo-sensitive source.")
}
function pinholediameter(){
	alert("The 'Pinhole Diameter' is the width in milimeters of the pinhole.")
}
function exposurefactor(){
	alert("The 'Exposure Factor' is the number to multiply by the timining metered by your camera, to get the timing for your pinhole camera.")
}
function cameraaperture(){
	alert("The 'Camera Aperture' the aperture or ' F Stop' you set on your SLR Camera.")
}
function cameraiso(){
	alert("The 'Camera ISO' is the ISO rating , or 'film speed' on your SLR Camera.")
}
function pinholeiso(){
	alert("The 'Pinhole ISO' is the ISO rating, or 'film speed' of the photosensitive material (typical for paper is 100 ISO).")
}
function shutterspeed(){
	alert("The 'Camera Shutter Speed' is shutter speed that your camera suggests to use at the set values.")
}