Changing a global variable from inside a function PHP

Question

I am trying to change a variable that is outside of a function, from within a function. Because if the date that the function is checking is over a certain amount I need it

Answer 1

Just use the global keyword like so:

$var = "01-01-10";
function checkdate(){
     global $var;

     if("Condition"){
            $var = "01-01-11";
      }
}

Any reference to that variable will be to the global one then.