Type:Function?, Attribute Type Description ------...">

Mozilla Developer Network - What is the Question Mark?

In Properties->"onreadystatechange"->Type:Function?,

Attribute           Type       Description
------------------------------------------
onreadystatechange  Function?  [...]
                            ^

What does it mean ??

+5
source share
1 answer

I'm not sure, but I think this means the value can be null.

+3
source

All Articles