Top "Undefined" questions

A variable is undefined if it has not been assigned a value.

What are all the common undefined behaviours that a C++ programmer should know about?

What are all the common undefined behaviours that a C++ programmer should know about? Say, like: a[i] = i++;

c++ undefined undefined-behavior c++-faq
Uncaught TypeError: Cannot call method 'toLowerCase' of undefined

I ran into a very vague error while doing some simple jQuery DOM manipulation. The line that triggered the error …

javascript jquery undefined typeerror
Uncaught TypeError: Cannot read property 'nodeName' of undefined

this problem appears only in joomla - im trying to use the contentflow plugin with my joomla site this is …

jquery joomla undefined typeerror
What does the compile-time error "Undefined symbols for architecture x86_64" mean?

I'm trying to program a graph class using an adjacent list from an example in my C++ text book, and …

compilation g++ undefined symbols
"Undefined function 'function_name' for input arguments of type 'double'."

A question that pops up quite frequently in different shapes and sizes is: Why do I get the following error …

matlab undefined octave
CoffeeScript Undefined

In javascript to check if a variable was never created, we just do if (typeof MyVariable !== "undefined"){ ... } I was wonder …

coffeescript undefined
JavaScript String concatenation behavior with null or undefined values

As you may know, in JavaScript '' + null = "null" and '' + undefined = "undefined" (in most browsers I can test: Firefox, …

javascript null undefined string-concatenation
How to handle Undefined Offset in laravel?

I am getting this error when I land on the page after logging in: ErrorException in compiled.php line 11573: Undefined …

php laravel undefined offset
Check if variable is false and not either true or undefined

What's the best way to check if myvar javascript variable === false or not (it may be undefined as well). if (…

javascript variables if-statement undefined
When do I initialize variables in JavaScript with null or not at all?

I have seen different code examples with variables declared and set to undefined and null. Such as: var a; // undefined …

javascript variables null undefined