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 nodename
- Cannot read property jspdf
- Cannot read property innertext
- Cannot read property xrm
- Cannot read property write
- Cannot read property json
- Cannot read property remove
- Cannot read property zoneid
- Cannot read property locals
- Cannot read property dataset
- Cannot read property mouse
- Cannot read property form
- Cannot read property toggle
- Cannot read property target
- Cannot read property split
- Cannot read property preventdefault
- Cannot read property reload
- Cannot read property jsonmodel
- Cannot read property keycode
- Cannot read property findindex
- Cannot read property removechild
- Cannot read property map
- Cannot read property firstchild
- Cannot read property queuedepthsort
- Cannot read property editor
- Cannot read property keyup
- Cannot read property parentnode
- Cannot read property submit
- Cannot read property reduce
- Cannot read property display
- Cannot read property uid
- Cannot read property element
- Cannot read property getelementsbyclassname
- Cannot read property version
- Cannot read property ngmodule
- Cannot read property view
- Cannot read property bind
- Cannot read property document
- Cannot read property value
- Cannot read property top
- Cannot read property setstate
- Cannot read property classlist
- Cannot read property html
- Cannot read property length
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- Cannot read property words
- Cannot read property foreach
- Cannot read property nodetype
- Cannot read property addeventlistener
- Cannot read property split
- Cannot read property xhr
- Cannot read property defaultview
- Cannot read property query
- Cannot read property append
- Cannot read property formatdate
- Cannot read property width