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
Undefined means that a variable has been declared, but the value of that variable has not yet been defined. In JavaScript, there are Undefined (type), undefined (value) and undefined (variable).
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). This error occurs when we want to access a property on a variable whose value is undefined or null.
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 name
- Cannot read property header
- Cannot read property history
- Cannot read property datatable
- Cannot read property 1
- Cannot read property set
- Cannot read property nodetype
- Cannot read property option
- Cannot read property innertext
- Cannot read property props
- Cannot read property hasattribute
- Cannot read property validate
- Cannot read property reduce
- Cannot read property remove
- Cannot read property view
- Cannot read property foreach
- Cannot read property json
- Cannot read property emit
- Cannot read property each
- Cannot read property jspdf
- Cannot read property y
- Cannot read property 10
- Cannot read property preventdefault
- Cannot read property map
- Cannot read property formatdate
- Cannot read property element
- Cannot read property readtext
- Cannot read property helpers
- Cannot read property async
- Cannot read property prototype
- Cannot read property bridge
- Cannot read property destroy
- Cannot read property touppercase
- Cannot read property write
- Cannot read property xlsx
- Cannot read property find
- Cannot read property ext
- Cannot read property constructor
- Cannot read property xhr
- Cannot read property type
- Cannot read property getattribute
- Cannot read property 2
- Cannot read property xrm
- Cannot read property hide
- Cannot read property height
- Cannot read property replace
- Cannot read property error
- Cannot read property xe
- Cannot read property location
- Cannot read property query
- Cannot read property top
- Cannot read property install
- Cannot read property ajax
- Cannot read property id
- Cannot read property browser
- Cannot read property version
- Cannot read property rows