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 :
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- Cannot read property validate
- Cannot read property browserwindow
- Cannot read property words
- Cannot read property browser
- Cannot read property touppercase
- Cannot read property join
- Cannot read property play
- Cannot read property queuedepthsort
- Cannot read property hide
- Cannot read property fn
- Cannot read property zone
- Cannot read property length
- Cannot read property version
- Cannot read property history
- Cannot read property set
- Cannot read property bind
- Cannot read property 3
- Cannot read property quesryselectorall
- Cannot read property top
- Cannot read property name
- Cannot read property rows
- Cannot read property slice
- Cannot read property render
- Cannot read property jspdf
- Cannot read property then
- Cannot read property append
- Cannot read property concat
- Cannot read property keyup
- Cannot read property dataset
- Cannot read property reset
- Cannot read property queryselector
- Cannot read property apply
- Cannot read property write
- Cannot read property map
- Cannot read property y
- Cannot read property uid
- Cannot read property preventdefault
- Cannot read property getitem
- Cannot read property error
- Cannot read property split
- Cannot read property destroy
- Cannot read property addeventlistener
- Cannot read property extend
- Cannot read property find
- Cannot read property sort
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- Cannot read property xe
- Cannot read property helpers
- Cannot read property ngmodule
- Cannot read property 1
- Cannot read property keycode
- Cannot read property type
- Cannot read property visible
- Cannot read property replace
- Cannot read property add
- Cannot read property mouse