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 name
• Cannot read property readtext
• Cannot read property rows
• Cannot read property element
• Cannot read property queryselector
• Cannot read property constructor
• Cannot read property addeventlistener
• Cannot read property innerhtml
• Cannot read property top
• Cannot read property call
• Cannot read property use
• Cannot read property height
• Cannot read property display
• Cannot read property ext
• Cannot read property history
• Cannot read property touppercase
• Cannot read property html
• Cannot read property hasownproperty
• Cannot read property y
• Cannot read property getters
• Cannot read property findindex
• Cannot read property uid
• Cannot read property 10
• Cannot read property set
• Cannot read property replace
• Cannot read property getcontext
• Cannot read property error
• Cannot read property bridge
• Cannot read property classname
• Cannot read property jsonmodel
• Cannot read property sort
• Cannot read property getelementsbyclassname
• Cannot read property length
• Cannot read property tolowercase
• Cannot read property getattribute
• Cannot read property adatasort
• Cannot read property helpers
• Cannot read property setattribute
• Cannot read property checked
• Cannot read property remove
• Cannot read property version
• Cannot read property files
• Cannot read property trim
• Cannot read property createdocumentfragment
• Cannot read property emit
• Cannot read property register
• Cannot read property slice
• Cannot read property get
• Cannot read property nodename
• Cannot read property appendchild
• Cannot read property match
• Cannot read property width
• Cannot read property innertext
• Cannot read property dataset
• Cannot read property have
• Cannot read property split
• Cannot read property tostring

Uncaught TypeError: Cannot read property '' of null