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 includes
- Cannot read property appendchild
- Cannot read property touppercase
- Cannot read property formatdate
- Cannot read property websiteid
- Cannot read property webkit
- Cannot read property indexof
- Cannot read property location
- Cannot read property foreach
- Cannot read property which
- Cannot read property then
- Cannot read property element
- Cannot read property remove
- Cannot read property visible
- Cannot read property y
- Cannot read property play
- Cannot read property length
- Cannot read property firstchild
- Cannot read property zoneid
- Cannot read property defaultview
- Cannot read property query
- Cannot read property nodetype
- Cannot read property preventdefault
- Cannot read property add
- Cannot read property add
- Cannot read property tostring
- Cannot read property top
- Cannot read property removechild
- Cannot read property ngmodule
- Cannot read property play
- Cannot read property emit
- Cannot read property set
- Cannot read property value
- Cannot read property 1
- Cannot read property bind
- Cannot read property helpers
- Cannot read property classlist
- Cannot read property nodename
- Cannot read property register
- Cannot read property jquery
- Cannot read property submit
- Cannot read property msie
- Cannot read property validate
- Cannot read property rows
- Cannot read property keyboard
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- Cannot read property document
- Cannot read property push
- Cannot read property mouse
- Cannot read property checked
- Cannot read property locals
- Cannot read property scrolltop
- Cannot read property init
- Cannot read property get
- Cannot read property form
- Cannot read property prototype