function interpret(toChange, offset) {
	var alphabet = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_.-@";
	var shifted = "";
	
	for (i = 0; i < toChange.length; i++) {
		index = alphabet.indexOf(toChange.charAt(i)) - offset;
	
		if (index < 0)
			index += alphabet.length;
	
		shifted += alphabet.charAt(index);
	}
	
	return(shifted);
}

function send_email(toChange, offset) {
	var address = interpret(toChange, offset);
	self.location.href="mailto:"+address;
}