The way how we can know or we can access to the global variables is with a build-in array in PHP named $GLOBALS where there are all the global variables that come with a key and a value.
I will show you a few examples in order that you can be familiar with this “special” array.
Analize the next example:
<html>
<head>
<title>This is a sample</title>
</head>
<body>
<?php
$carModel = "Tesla";
function example(){
$carModel = "Nio";
echo "The current \$carModel variable is $carModel \n\t\t";
echo "The global \$carModel variable is ".$GLOBALS["carModel"];
}
example();
?>
</body>
</html>
First of all, we can notice that the php script is embedded in a html file, I did this in that way because the code is small and is manageable to keep it within a html file.
The important thing to notice is that we have two variables with the same name; carModel but one variable is inside the function example and the other can be considered as a global variable. We can access to the global variable with the array previosly mentioned ($GLOBALS).
The main advantage here is that we don´t need to use the global prefix before to declarate a global variable and as well, we can access to any global variable in a easy way.