Php表达式 - 如果$ b有内容，则隐藏$ a

Question

I am trying to setup an expression for an href. Basically I want the url to change if the user adds a manual one in the backend.

I am using Advanced Custom Fields.

So I have 2 custom fields and would like custom field A to be cleared if field B has a url. Field A is always generated by the cms (like a randon link).

To explain better so you get the concept basically I want the user to be able to enter their manual link rather than the generated one if i am making my self clear.

So basically if Field B is true Clear field A which again is an href link.

I am pretty sure that this is a basic php statement just started with php :P

Answer 1

$a = $_POST['a'];
$b = $_POST['b'];

if ($b != '') $a = null;