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 slice
- Cannot read property getelementsbytagname
- Cannot read property addeventlistener
- Cannot read property xlsx
- Cannot read property msie
- Cannot read property indexof
- Cannot read property id
- Cannot read property add
- Cannot read property use
- Cannot read property 3
- Cannot read property data
- Cannot read property append
- Cannot read property fn
- Cannot read property 10
- Cannot read property y
- Cannot read property nodename
- Cannot read property style
- Cannot read property setstate
- Cannot read property write
- Cannot read property remove
- Cannot read property hide
- Cannot read property getattribute
- Cannot read property defaultview
- Cannot read property zone
- Cannot read property reduce
- Cannot read property click
- Cannot read property 2
- Cannot read property query
- Cannot read property view
- Cannot read property apply
- Cannot read property name
- Cannot read property validate
- Cannot read property parentnode
- Cannot read property adatasort
- Cannot read property datatable
- Cannot read property html
- Cannot read property words
- Cannot read property error
- Cannot read property tolowercase
- Cannot read property get
- Cannot read property option
- Cannot read property x
- Cannot read property header
- Cannot read property mouse
- Cannot read property getitem
- Cannot read property focus
- Cannot read property createelement
- Cannot read property bind
- Cannot read property tostring
- Cannot read property keycode
- Cannot read property ngmodule
- Cannot read property replace
- Cannot read property rows
- Cannot read property document
- Cannot read property sort
- Cannot read property prototype
- Cannot read property trim