23107 - prompt() does not return exactly null on cancel

Status: VERIFIED DUPLICATE of bug 12021

(SeaMonkey :: UI Design, defect, P3)

Description

[Ben Goodger (use ben at mozilla dot org for email)]

clicking cancel on the prompt() dialog should return exactly null (Flanagan,
p737). Thus, the following alert box should be displayed only after the user
clicks cancel on the dialog due to the identity operator:

if( prompt("Foo","") === null )
{
   alert("Foo is EXACTLY equal to null");
}

however this is not the case. not even equality comparison (==) with null seems
to work, although the value returned is some kind of value that displays as
an empty string.

Comment 1

[davidm]

*** This bug has been marked as a duplicate of 12021 ***

Comment 2

[Alan S. Jones]

verified dup of 12021 "Javascript prompt is returning bogus value"