Property attribute (Definition)

A property can have zero or more attributes.


ECMAScript edition - 2

A property can have zero or more attributes. The attributes control how the property is accessed both internally from inside the interpreter and externally from your script.

Here is a list of the property attributes defined by the ECMA Script standard:

ReadOnlyThe property is a read-only value. Scripts will not be allowed to change the value although the value may change from time to time if it is dependant on some host related facility.
DontEnumYou cannot enumerate this property with a repetition.
DontDeleteYou cannot delete this property.
InternalThis is an internal property, which you normally won't have any access to. It's likely it would be hidden inside the host-managed objects and inaccessible to your scripts.

Where properties are ReadOnly, this is flagged in the documentation. Read/write access is assumed to be the default case otherwise.

There is conflicting information in the reference sources regarding the read/write ability of some properties. Some suggest a particular property is ReadOnly and other suggest you can assign a value to it. It may be that you can assign a value to it without the JavaScript interpreter complaining but that any value you assign is ignored.

See also:delete, Object, Property


ECMA 262 edition 2 - section - 8.6.1

ECMA 262 edition 3 - section - 8.6.1