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 type
- Cannot read property getitem
- Cannot read property get
- Cannot read property xe
- Cannot read property browserwindow
- Cannot read property jquery
- Cannot read property reduce
- Cannot read property defaultview
- Cannot read property sort
- Cannot read property ngmodule
- Cannot read property keyboard
- Cannot read property nodename
- Cannot read property browser
- Cannot read property reload
- Cannot read property visible
- Cannot read property init
- Cannot read property map
- Cannot read property location
- Cannot read property removechild
- Cannot read property html
- Cannot read property createelement
- Cannot read property words
- Cannot read property submit
- Cannot read property y
- Cannot read property x
- Cannot read property datatable
- Cannot read property destroy
- Cannot read property apply
- Cannot read property xhr
- Cannot read property split
- Cannot read property height
- Cannot read property nodetype
- Cannot read property queryselector
- Cannot read property emit
- Cannot read property hide
- Cannot read property zoneid
- Cannot read property bind
- Cannot read property target
- Cannot read property ajax
- Cannot read property adatasort
- Cannot read property helpers
- Cannot read property hasownproperty
- Cannot read property append
- Cannot read property hasattribute
- Cannot read property top
- Cannot read property quesryselectorall
- Cannot read property addeventlistener
- Cannot read property write
- Cannot read property websiteid
- Cannot read property version
- Cannot read property trim
- Cannot read property getters
- Cannot read property find
- Cannot read property add
- Cannot read property 1
- Cannot read property focus
- Cannot read property option