Question

How can I make “GET” understand the number 0 without it understanding that 0 is nothing?

if(empty($_GET['number'])) {
echo "No GET variables"; 
}

if($_GET['number']){
$number=strip_tags(addslashes(htmlspecialchars($_GET['number'])));
echo $number;
}

If the variable “number” = 1 it will echo “1” but if the number is 0 it will echo “No GET variables”

How can I make it understand 0 as well as other numbers?

Answer 1

empty returns true if you give it a 0; you can use isset instead to check whether it is set (regardless of value):

if(isset($_GET['number']))

from http://php.net/empty:

Returns FALSE if var has a non-empty and non-zero value.

The following things are considered to be empty:

• "" (an empty string)
• 0 (0 as an integer)
• 0.0 (0 as a float)
• "0" (0 as a string)
• NULL
• FALSE
• array() (an empty array)
• var $var; (a variable declared, but without a value in a class)

My test:

$_GET['number'] = "0";
assert(isset($_GET['number']));

$_GET['number'] = 0;
assert(isset($_GET['number']));

Your code should look like:

if(!isset($_GET['number'])) {
   echo "No GET variables"; 
}

if(isset($_GET['number'])) {
   $number=strip_tags(addslashes(htmlspecialchars($_GET['number'])));
   echo $number;
}

Or more concise

if(!isset($_GET['number'])) {
   echo "No GET variables"; 
} else {
   $number=strip_tags(addslashes(htmlspecialchars($_GET['number'])));
   echo $number;
}