(PHP 4, PHP 5, PHP 7)
  Often you'd want to execute a statement if a certain condition is
  met, and a different statement if the condition is not met.  This
  is what else is for.  else
  extends an if statement to execute a statement
  in case the expression in the if statement
  evaluates to FALSE.  For example, the following
  code would display a is greater than
  b if $a is greater than
  $b, and a is NOT greater
  than b otherwise:
  
<?php
if ($a > $b) {
  echo "a is greater than b";
} else {
  echo "a is NOT greater than b";
}
?>
FALSE, and if there were any
  elseif expressions - only if they evaluated to
  FALSE as well (see elseif).