Type juggling in PHP - what it is and why it matters

In PHP, a variable type is decided by it's value. If a variable contains a number then it's type is integer. If we update the value of the variable in the next line to a string, then it's type becomes string.

So, the value of the variable automate the variable type. Hence PHP is a dynamically typed language. This automatic type conversion in PHP is called type juggling.

Let's define a variable $temp and assign an integer 10. Using function gettype() finds it's a numeric variable.
$temp = 10;
echo gettype($temp);

Now, assign a string in the same variable. It's type now becomes string.
$temp = "Hello";
echo gettype($temp);

Again, assign a boolean value in the same variable. It's type now becomes boolean.
$temp = true;
echo gettype($temp);

So, different values in the same variable in three successive lines juggling with three different data types.

Type juggling sometimes caused vulnerabilities. The most common vulnerability arises with the user authentication. Therefore, developers have to be careful when using type juggling, especially when comparing values.

Видео Type juggling in PHP - what it is and why it matters канала PHP Explained