What is the common mistake made in PHP code where a line is missing in the output?

The common mistake made in PHP code where a line is missing in the output is forgetting to include the "echo" or "print" statement to display the desired output. Without this statement, the code may execute correctly but the expected output will not be shown on the screen. To solve this issue, simply add an "echo" or "print" statement before the variable or text that needs to be displayed.

// Incorrect code without echo statement
$name = "John Doe";
$name; // This line is missing the echo statement

// Corrected code with echo statement
$name = "John Doe";
echo $name; // This line includes the echo statement to display the output