Undefined variable issue with PHP
19574
undefined offset PHP error
70032
How do I set a variable in the configuration file setting.php and use it from code?
37735
How can I check for "undefined" in JavaScript?
37229
Fatal error: Call to undefined method mysqli_result::fetch_all()
85610
Undefined index in PHP post
131630
Using braces with dynamic variable names in PHP
24433
Error handling in PHP
132987
Fixing the PHP empty function
5123
PHP variable variables
42903
PHP eval issue with PHP + HTML code
76704
Undefined variable: $_SESSION
80143
Pass PHP variable from one page to another and to another
49446
How to check for an undefined or null variable in JavaScript?
53203
Checking for undefined
50978
PHP some $_POST values missing but are present in php://input
55096
Javascript and PHP functions
105287
(Why) is using an uninitialized variable undefined behavior?