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 dataset
• Cannot read property webkit
• Cannot read property nodename
• Cannot read property key
• Cannot read property rows
• Cannot read property constructor
• Cannot read property 10
• Cannot read property jsonmodel
• Cannot read property createdocumentfragment
• Cannot read property emit
• Cannot read property async
• Cannot read property json
• Cannot read property locals
• Cannot read property tolowercase
• Cannot read property readtext
• Cannot read property textcontent
• Cannot read property find
• Cannot read property init
• Cannot read property id
• Cannot read property 2
• Cannot read property register
• Cannot read property uid
• Cannot read property getcontext
• Cannot read property target
• Cannot read property browser
• Cannot read property getitem
• Cannot read property hasattribute
• Cannot read property words
• Cannot read property includes
• Cannot read property display
• Cannot read property each
• Cannot read property addeventlistener
• Cannot read property createelement
• Cannot read property concat
• Cannot read property zone
• Cannot read property append
• Cannot read property parentnode
• Cannot read property play
• Cannot read property mouse
• Cannot read property y
• Cannot read property adatasort
• Cannot read property nodetype
• Cannot read property length
• Cannot read property hasownproperty
• Cannot read property call
• Cannot read property toggle
• Cannot read property editor
• Cannot read property zoneid
• Cannot read property header
• Cannot read property destroy
• Cannot read property getters
• Cannot read property remove
• Cannot read property write
• Cannot read property formatdate
• Cannot read property files
• Cannot read property queuedepthsort
• Cannot read property replace

Uncaught TypeError: Cannot read property '' of null