function checkInput() {
	var name = document.register.name.value;
	var email = document.register.email.value;
	var password =	document.register.password.value;
	var password_verify = document.register.password_verify.value;

	var error = "";

	if (name.length == 0) { error += "ERROR: Invalid name.<br>\n"; }
	if (checkMail(email) == false) { error += "ERROR: Invalid email address.<br>\n"; }
	
	// check password
	if (password.length < 5) {
		error += "ERROR: Your password must be at least five characters.<br>\n";
	} else if (password.toLowerCase() != password_verify.toLowerCase()) {
		error += "ERROR: Your passwords don't match.<br>\n";
	}
	
	if (error) {
		printError(error);
	} else {
		document.register.submit();
	}
}

// print the error
function printError(error) {
	if (document.register.cell_contents.value == "") { // remember old value
		document.register.cell_contents.value = document.getElementById('menu').innerHTML;
	}
	error = "<p class=\"message\">" + error + "</p>\n";
	error += "<p class=\"small\"><a href=\"javascript:clearError()\">[Clear Error Message]</a></p>";
	document.getElementById('menu').innerHTML = error;
}

// clear the error
function clearError() {
	document.getElementById('menu').innerHTML = document.register.cell_contents.value;
}