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 write
- Cannot read property left
- Cannot read property browser
- Cannot read property getters
- Cannot read property error
- Cannot read property key
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- Cannot read property extend
- Cannot read property adatasort
- Cannot read property split
- Cannot read property data
- Cannot read property parentnode
- Cannot read property sort
- Cannot read property nodename
- Cannot read property submit
- Cannot read property getelementsbytagname
- Cannot read property jsonmodel
- Cannot read property top
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- Cannot read property textcontent
- Cannot read property defaultview
- Cannot read property editor
- Cannot read property bridge
- Cannot read property hasownproperty
- Cannot read property getitem
- Cannot read property zone
- Cannot read property element
- Cannot read property remove
- Cannot read property 2
- Cannot read property height
- Cannot read property length
- Cannot read property websiteid
- Cannot read property add
- Cannot read property getattribute
- Cannot read property keycode
- Cannot read property 3
- Cannot read property call
- Cannot read property click
- Cannot read property html
- Cannot read property 10
- Cannot read property validate
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- Cannot read property set
- Cannot read property browserwindow
- Cannot read property helpers
- Cannot read property checked
- Cannot read property queryselector
- Cannot read property ajax
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- Cannot read property readtext
- Cannot read property reload