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 push
- Cannot read property version
- Cannot read property classlist
- Cannot read property ngmodule
- Cannot read property queryselector
- Cannot read property target
- Cannot read property nodename
- Cannot read property document
- Cannot read property name
- Cannot read property bridge
- Cannot read property render
- Cannot read property getitem
- Cannot read property init
- Cannot read property type
- Cannot read property datatable
- Cannot read property firstchild
- Cannot read property location
- Cannot read property option
- Cannot read property filter
- Cannot read property style
- Cannot read property join
- Cannot read property preventdefault
- Cannot read property jspdf
- Cannot read property locals
- Cannot read property width
- Cannot read property ext
- Cannot read property tolowercase
- Cannot read property xlsx
- Cannot read property props
- Cannot read property files
- Cannot read property call
- Cannot read property apply
- Cannot read property xe
- Cannot read property async
- Cannot read property mouse
- Cannot read property emit
- Cannot read property innerhtml
- Cannot read property find
- Cannot read property createdocumentfragment
- Cannot read property getelementsbytagname
- Cannot read property each
- Cannot read property reload
- Cannot read property jquery
- Cannot read property play
- Cannot read property helpers
- Cannot read property scrolltop
- Cannot read property display
- Cannot read property readtext
- Cannot read property slice
- Cannot read property visible
- Cannot read property state
- Cannot read property removechild
- Cannot read property webkit
- Cannot read property remove
- Cannot read property msie
- Cannot read property rows
- Cannot read property xhr