function changeSubmit(submitButton) {
	var button=document.getElementById(submitButton);
	if (button.disabled == true) {
		button.value='Send';
		button.disabled=false;
	} else {
		button.value='Checking...';
		button.disabled=true;
	}
}
function checkContactForm(form){
	changeSubmit('submitForm');
	if (document.contactForm.name.value == ""){
		alert ('Please enter your name.');
		document.contactForm.name.focus();
		changeSubmit('submitForm');
		return false;
	}
	if (document.contactForm.email.value == ""){
		alert ('Please enter your Email address.');
		document.contactForm.email.focus();
		changeSubmit('submitForm');
		return false;
	}
	if (checkEmailAddress(document.contactForm.email.value)==false){
		alert ('Please enter a valid Email address.');
		document.contactForm.email.focus();
		changeSubmit('submitForm');
		return false;
	}
	if (document.contactForm.message.value == ""){
		alert ('Please tell us how we can help you.');
		document.contactForm.message.focus();
		changeSubmit('submitForm');
		return false;
	}
	if (checkMessageField(document.contactForm.message.value)==false){
		alert ('Your message looks like spam! Please remove the http:// part of the web address in your message.');
		document.contactForm.message.focus();
		changeSubmit('submitForm');
		return false;
	}
	form.submitForm.value='Sending...';
	return true;
}
function checkMessageField(emailMessage){
	var notAllowed = "http";
	var messageField = emailMessage;
	if (messageField.indexOf(notAllowed) != -1){
		return (false);
	}
	return (true);
}
function checkEmailAddress(emailAddress){
	var allowed = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789.@-_";
	var emailLength = emailAddress.length;
	var atSignPosition = 0;
	var finalDotPosition = 0;
	var numberOfDots = 0;
	var numberOfAtSigns = 0;
	if (emailLength < 5){
		return false;
	}
	for (i = 0; i < emailLength ;i ++){
		if (allowed.indexOf(emailAddress.charAt(i))<0){
			return (false);
		}
		if ((emailAddress.charAt(i)) == "@"){
			numberOfAtSigns ++;
			atSignPosition = i;
		} else {
			if ((emailAddress.charAt(i)) == "."){
				numberOfDots ++;
				finalDotPosition = i;
			}
		}
	}
	if (numberOfDots == 0){
		return (false);
	}
	if (numberOfAtSigns != 1){
		return (false);
	}
	if (atSignPosition > finalDotPosition){
		return (false);
	}
	if (finalDotPosition == (emailLength-1)){
		return (false);
	}
	return (true);
}