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 xe
- Cannot read property getitem
- Cannot read property install
- Cannot read property ajax
- Cannot read property element
- Cannot read property y
- Cannot read property use
- Cannot read property add
- Cannot read property createelement
- Cannot read property rows
- Cannot read property bind
- Cannot read property hide
- Cannot read property version
- Cannot read property reduce
- Cannot read property queryselector
- Cannot read property xhr
- Cannot read property firstchild
- Cannot read property tostring
- Cannot read property addeventlistener
- Cannot read property getters
- Cannot read property init
- Cannot read property which
- Cannot read property render
- Cannot read property textcontent
- Cannot read property toggle
- Cannot read property keycode
- Cannot read property editor
- Cannot read property trim
- Cannot read property quesryselectorall
- Cannot read property top
- Cannot read property slice
- Cannot read property createdocumentfragment
- Cannot read property words
- Cannot read property getattribute
- Cannot read property error
- Cannot read property bind
- Cannot read property bridge
- Cannot read property add
- Cannot read property then
- Cannot read property getelementsbyclassname
- Cannot read property parentnode
- Cannot read property setstate
- Cannot read property split
- Cannot read property msie
- Cannot read property classlist
- Cannot read property keyup
- Cannot read property prototype
- Cannot read property reload
- Cannot read property remove
- Cannot read property foreach
- Cannot read property browserwindow
- Cannot read property 1
- Cannot read property map
- Cannot read property filter
- Cannot read property append
- Cannot read property visible