What common mistake was made in the PHP code provided for the counter?

The common mistake in the provided PHP code for the counter is that the counter variable is not being properly incremented within the loop. To solve this issue, we need to increment the counter variable inside the loop to keep track of the number of iterations.

$counter = 0;

for ($i = 0; $i < 10; $i++) {
    $counter++;
    echo "Iteration: " . $counter . "<br>";
}