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 :
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- Cannot read property adatasort
- Cannot read property zoneid
- Cannot read property reset
- Cannot read property width
- Cannot read property query
- Cannot read property click
- Cannot read property submit
- Cannot read property play
- Cannot read property jquery
- Cannot read property nodename
- Cannot read property replace
- Cannot read property ngmodule
- Cannot read property xhr
- Cannot read property classlist
- Cannot read property parentnode
- Cannot read property split
- Cannot read property target
- Cannot read property append
- Cannot read property keyup
- Cannot read property contains
- Cannot read property version
- Cannot read property xe
- Cannot read property jspdf
- Cannot read property pending
- Cannot read property getelementsbyclassname
- Cannot read property id
- Cannot read property push
- Cannot read property createelement
- Cannot read property emit
- Cannot read property remove
- Cannot read property reload
- Cannot read property have
- Cannot read property focus
- Cannot read property get
- Cannot read property websiteid
- Cannot read property bind
- Cannot read property visible
- Cannot read property split
- Cannot read property addeventlistener
- Cannot read property tolowercase
- Cannot read property bridge
- Cannot read property set
- Cannot read property zindex
- Cannot read property constructor
- Cannot read property setstate
- Cannot read property option
- Cannot read property form
- Cannot read property display
- Cannot read property 3
- Cannot read property install
- Cannot read property prototype
- Cannot read property bind
- Cannot read property x
- Cannot read property rows
- Cannot read property slice
- Cannot read property value