function validate(f) { 
	if (isBlank(f.forename.value)) {
		alert("Please enter your forename");
		f.forename.focus();
		return false;
	}
	if (isBlank(f.surname.value)) {
		alert("Please enter your surname");
		f.surname.focus();
		return false;
	}
	if (isBlank(f.email.value)) {
		alert("Please enter a email");
		f.email.focus();
		return false;
	}
	if (!isEmail(f.email.value)) {
		alert("The email you supplied is invalid!");
		f.email.focus();
		return false;
	}
	if (isBlank(f.message.value)) {
		alert("Please enter a message");
		f.message.focus();
		return false;
	}
	return true
}


function isBlank(v) {
	if ((v.length>0) && (v!=" ")) {
		return false;
	}
	else {
		return true;
	}
}

function isEmail(v) {
	at=v.indexOf('@');
	dot=v.lastIndexOf('.');
	end=v.length;
	subone=v.substring(at+1,dot);
	domainbeforedot=subone.length;
	subtwo=v.substring(dot+1,end);
	domainafterdot=subtwo.length;
   	if (v.indexOf ('@',0) == -1 || v.indexOf ('.',0) == -1  || domainbeforedot < 1 || domainafterdot < 2 ) {
      		return false;
	}
   	else { 
   		return true; 
   	}
}