function checkForm() {
	name = document.getElementById("name").value;
  email = document.getElementById("email").value;
	subject = document.getElementById("subject").value;
  message = document.getElementById("message").value;
  error = 0; //error handler

	//validate name
	var nameFilter = /[\W_] /;
  // allow only letters, numbers and spaces
 	if (nameFilter.test(name)) {
		error = 1;
		document.getElementById("nameError").className = "error";
		document.getElementById("warning").style.display = "block";
	} else {
		document.getElementById("nameError").className = "noError";
	}
	
	//validate email address
	var emailFilter=/^.+@.+\..{2,3}$/;
	if (!(emailFilter.test(email))) { 
		error = 1;
		document.getElementById("emailError").className = "error";
		document.getElementById("warning").style.display = "block";
	} else {
		var emailIllegal =  /[\(\)\<\>\,\;\:\\\"\[\]]/;
		if (email.match(emailIllegal)) {
			error = 1;
			document.getElementById("emailError").className = "error";
			document.getElementById("warning").style.display = "block";
		}else {
			document.getElementById("emailError").className = "noError";
		}
	}
	
	//validate subject
 	if (subject == "") {
		error = 1;
		document.getElementById("subjectError").className = "error";
		document.getElementById("warning").style.display = "block";
	} else {
		document.getElementById("subjectError").className = "noError";
	}
	
	//validate message
	if (message == "") {
		error = 1;
		document.getElementById("messageError").className = "error";
		document.getElementById("warning").style.display = "block";
	} else {
		document.getElementById("messageError").className = "noError";
	}
	
	//if error, then don't submit form
	if (error == "1"){	
		return false;
	}
	
	//else submit form
  return true;
}

function checkButton() {
	name = document.getElementById("name").value;
	email = document.getElementById("email").value;
	subject = document.getElementById("subject").value;
	message = document.getElementById("message").value;

	//if fields are not blank, enable form button
	if (name != "" && email != "" && subject != "" && message != "") {
		document.getElementById("button").disabled = false;
	} else {
		document.getElementById("button").disabled = true;
	}
}

function disableButton() {
	//if JavaScript enabled, disable form button
	document.getElementById("button").disabled = true;
}