function CheckValidPassword (strng) {
 var error = "";
 if (strng == "") {
    error = "You didn't enter a password.\n";
 }
    var illegalChars = /[\W_]/; // allow only letters and numbers
    if ((strng.length < 6) || (strng.length > 12)) {
       error = "Your password must be between 6 and 12 characters in length.\n";
    }
    else if (illegalChars.test(strng)) {
      error = "Your password contains illegal characters. Only letters A-Z and numbers 0-9 are allowed\n";
    }
	return error
 }