function check_form(form) {

	// Contact Form
	if (form.id == "contact_form") {
		
		// E-mail
		if (form.email.value == "") {
			alert("Please fill in your e-mail address.");
			form.email.focus();
			return false;
		}
	
	// Questionnaire
	} else if (form.id == "ques_form") {
	
		// Project Name
		if (form.proj_name.value == "") {
			alert("Please fill in the project name.");
			form.proj_name.focus();
			return false;
		}
		
		// Type of Facility
		if (form.facility.value == "") {
			alert("Please fill in the type of facility.");
			form.facility.focus();
			return false;
		}
		
		// Water Use
		if (form.water_use.value == "") {
			alert("Please fill in the use of the water.");
			form.water_use.focus();
			return false;
		}
		
		// Perceived water problem
		if (form.problem.value == "") {
			alert("Please fill in the perceived water problem.");
			form.problem.focus();
			return false;
		}
		
		// Available Pressure
		if (form.avail_pressure.value == "") {
			alert("Please fill in the available pressure (PSI).");
			form.avail_pressure.focus();
			return false;
		}
		
		// Needed Pressure
		if (form.need_pressure.value == "") {
			alert("Please fill in the needed pressure.");
			form.need_pressure.focus();
			return false;
		}
		
		// Available Space
		
			// Length
			if (form.space_l.value == "") {
				alert("Please fill in the available space length.");
				form.space_l.focus();
				return false;
			}
			
			// Width
			if (form.space_w.value == "") {
				alert("Please fill in the available space width.");
				form.space_w.focus();
				return false;
			}
			
			// Height
			if (form.space_h.value == "") {
				alert("Please fill in the available space height.");
				form.space_h.focus();
				return false;
			}
			
		// Smallest Doorway for Access
		
			// Length
			if (form.doorway_l.value == "") {
				alert("Please fill in the smallest doorway for access length.");
				form.doorway_l.focus();
				return false;
			}
			
			// Width
			if (form.doorway_w.value == "") {
				alert("Please fill in the smallest doorway for access width.");
				form.doorway_w.focus();
				return false;
			}
			
			// Height
			if (form.doorway_h.value == "") {
				alert("Please fill in the smallest doorway for access height.");
				form.doorway_h.focus();
				return false;
			}
			
		// E-mail
		if (form.email.value == "") {
			alert("Please fill in your e-mail address.");
			form.email.focus();
			return false;
		}
	
	} else {
		alert("The form \""+form.id+"\" could not be found.");
		return false;
	}
	return true;
}