Uncaught TypeError: Cannot read property '' of undefined
JavaScript Error: Uncaught TypeError: Cannot read property '' of null
JavaScript TypeError is returned when an operand or argument passed to a function is incompatible with the type expected by that operator or function. This error occurs in the browser when you read a property or call a method on an undefined object.
There are a few variations of this error depending on the property you are trying to access. Sometimes instead of undefined it will output null:
Uncaught TypeError: Cannot read property '' of null
Cannot read property '' of undefined
Cannot read property '' of null
Simply put, undefined means that a variable has been declared but has not yet been given a value. This particular error is probably the easiest to understand from an undefined point of view, because undefined is not considered an object type at all (but its own undefined type instead), and properties cannot belong to only to objects in JavaScript.
This error occurs when we want to access a property on a variable whose value is undefined or null. This error occurs when you try to call a method or try to access a property of a variable that does not exist (is not an object).
Null vs. Undefined in JavaScript The value "undefined" indicates that a variable has been declared, but no value has been assigned. On the other hand, "null" refers to a non-existent object, which basically means "empty" or "nothing". These are two values generally used to indicate the absence of something. Also, undefined and null are two distinct types: undefined is a type itself (undefined) while null is an object.
Other Javascript errors :
- Cannot read property reset
- Cannot read property match
- Cannot read property add
- Cannot read property 10
- Cannot read property sort
- Cannot read property removechild
- Cannot read property dataset
- Cannot read property view
- Cannot read property apply
- Cannot read property datatable
- Cannot read property queryselector
- Cannot read property play
- Cannot read property join
- Cannot read property keyboard
- Cannot read property bind
- Cannot read property constructor
- Cannot read property id
- Cannot read property target
- Cannot read property remove
- Cannot read property 2
- Cannot read property have
- Cannot read property xe
- Cannot read property hasownproperty
- Cannot read property browser
- Cannot read property ngmodule
- Cannot read property focus
- Cannot read property install
- Cannot read property textcontent
- Cannot read property zoneid
- Cannot read property toggle
- Cannot read property zone
- Cannot read property 1
- Cannot read property includes
- Cannot read property version
- Cannot read property document
- Cannot read property hide
- Cannot read property error
- Cannot read property jspdf
- Cannot read property mouse
- Cannot read property browserwindow
- Cannot read property parentnode
- Cannot read property then
- Cannot read property register
- Cannot read property map
- Cannot read property render
- Cannot read property append
- Cannot read property html
- Cannot read property reduce
- Cannot read property innerhtml
- Cannot read property setattribute
- Cannot read property rows
- Cannot read property call
- Cannot read property form
- Cannot read property async
- Cannot read property length
- Cannot read property extend
- Cannot read property addmethod