I've been asked to validate the booking reference of an App. here is the task: Although the client-side validation checks the correct form of the booking reference, it does not actually check it is a valid booking reference. For a reference to be valid, the server-side should validate the reference to the same format as the client-side, plus the following additional constraints: the three-letter group must be one of "ABC", "ACD", "BCD". Anything else is invalid. The next character must be a hyphen. Anything else is invalid. The first digit may only be 5 or 8. The other digits may be any value between 0 and 9 inclusive. You need to provide checks and only if all are valid, proceed to write the data to the database. If not, provide feedback to the user that the booking reference is invalid. Add a comment to your validation code explaining the meaning of each part of your booking reference validation expression. Again, examine the existing code closely, it will guide you. The easiest way to test regular expressions is using a free online tool - search the web for 'regex tester' to discover these. my code doesn't work and I don't know why:

$value = $data['bookingref'];

// ^ = anchor, [ABCACDBCD] = one of the three-letter group, - = hyphen, [58] = first digit, [0-9] = other digits

$format = "/^[ABCACDBCD]-[58][0-9]{5}$/";

// If value does NOT match the format then it is invalid

if (!preg_match($format, $value)) {

$feedback['bookingref'] = 'Server feedback: Invalid booking reference format';

$valid = false;

}

The hyphen doens't work at all. When I go on admin.js here is what I did. Probably there's something wrong with that too? .

if (inputElement.id == "bookingref") {

// ^$ = anchors, [a-zA-Z0-9] = letters/digits/spaces, \-= one - symbol, * = 0 or more characters

pattern = /^[a-zA-Z0-9 ]*$/, /^.+\-.+$/; feedback = "Only letters, numbers and hypen are permitted"; Here's what it shows when I try to insert the ref number.

Server feedback: Invalid booking reference format