Top "Undefined" questions

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

FancyBox iframe returns parent.$ as undefined (using WordPress)

I'm trying to close FancyBox from within the iframe, but parent.$ is always undefined. This is my iframe JavaScript: <…

jquery wordpress iframe fancybox undefined
Pass array from controller to view - Codeigniter

I tried to print the array in the controller, before passing it to a view and this is the output …

php codeigniter undefined pass-data
is there any function like string.isnullorempty() in javascript

I always (thing != undefined || thing != null)?...:...; check. Is there any method will return bool after this check in javascript or …

javascript jquery null undefined
Why is there a `null` value in JavaScript?

In JavaScript, there are two values which basically say 'I don't exist' - undefined and null. A property to which …

javascript null language-features undefined
undefined method `devise_for' in rails

After I install devise and create a user model. I rake db:migrate and then I rake routes. I then …

ruby-on-rails methods devise undefined
JavaScript - Identify whether a property is defined and set to 'undefined', or undefined

Say I have the following code: function One() {} One.prototype.x = undefined; function Two() {} var o = new One(); var t = …

javascript object properties undefined
Is it possible in PHP to prevent "Fatal error: Call to undefined function"?

In PHP, is there any way that I can ignore functions that are undefined instead of throwing a fatal error …

php error-handling undefined fatal-error
Returning const reference to local variable from a function

I have some questions on returning a reference to a local variable from a function: class A { public: A(int …

c++ reference undefined const-reference
Undefined function sha256()

I have this php code: $password = sha256($_POST['password']); but when I run this code it says: Fatal error: Call …

php cryptography undefined trim sha256
Why is this object property undefined?

Consider the code below. The first console.log correctly logs the image, and you can see its properties in the …

javascript object undefined object-properties