function check_contact_form(form) { 
	var msg = "The following fields are mandatory (*):\r\n";
	var flag = true; 
	if (form.txtMessage.value=="") {
		msg += "  - Message\r\n";
		flag = false;
	}
	if (form.txtName.value=="") {
		msg += "  - Name\r\n";		
		flag = false;
	}
	if (form.txtCompany.value=="") {
		msg += "  - Company\r\n";		
		flag = false;
	}
	if (form.txtEmail.value=="") {
		msg += "  - Email\r\n";		
		flag = false;
	}
	if (form.txtAddress.value=="") {
		msg += "  - Address\r\n";		
		flag = false;
	}
	if (form.txtCountry.value=="") {
		msg += "  - Country\r\n";		
		flag = false;
	}
	if (form.txtPhone.value=="") {
		msg += "  - Phone\r\n";		
		flag = false;
	}
	
	if (flag == false) {
		alert(msg);
		if (form.txtMessage.value == "") {
			form.txtMessage.focus();
		}else if (form.txtName.value == "") {
			form.txtName.focus();
		}else if (form.txtCompany.value == "") {
			form.txtCompany.focus();
		}else if (form.txtEmail.value == "") {
			form.txtEmail.focus();
		}else if (form.txtAddress.value == "") {
			form.txtAddress.focus();
		}else if (form.txtCountry.value == "") {
			form.txtCountry.focus();
		}else if (form.txtPhone.value == "") {
			form.txtPhone.focus();
		}
		return false;
	} else {
		if (!check_email(form.txtEmail.value)) {
			alert ("Invalid email address");
			form.txtEmail.focus();
			return false
		}
	}
	
	return true;
}

function check_email(sInput){ 
	var filter  = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
	if (filter.test(sInput)) 
		return true;
	else 
		return false;
}