Defining a property with the DontEnum attribute

[Howard Jess]

All --

I'm trying to solve a problem for which I think the solution will be
to *cheat*; but I don't mind doing so for this case. The background is:

Given an object constructor, and an instance

SampleObj = function() {
this.prop = 1;
}
obj = new SampleObj();
obj has one enumerable property: 'prop'; and several builtin,
non-enumerable properties as well: 'toString', 'hasOwnProperty ',
'propertyIsEnum erable', etc. If I redefined any of those, e.g:

SampleObj.proto type.toString = function() {return '[SampleObj]'};

then obj still has only one enumerable property; the redefinition of
toString doesn't affect its "DontEnum"-ness.

I'd like to be able to create such a property from JavaScript. In
particular, in older versions of Safari, some of those required properties
aren't implemented (hasOwnProperty , isPrototypeOf, propertyIsEnume rable,
& toLocaleString) . If I define them myself:

Object.prototyp e.toLocaleStrin g = Object.prototyp e.toString;
[etc.]

then they are enumerable, which causes problems for code like

for (var prop in obj) ...

I'll get a different set of enumerated properties in Safari than in (e.g.)
Mozilla; and have to specifically check for those that I defined myself,
to make code work appropriately on each browser. This gets tricky
(considering that the old Safari versions also failed to implement
toExponential, toFixed and toPrecision for Number objects).

The ability to set the DontEnum and ReadOnly attributes of object
properties would have been great; but (afaik) there is no way to do so. So
I'm looking for a "backdoor" in Safari that would allow this.

Help anyone?
Howard Jess

[hj]

RobG wrote:

Howard Jess wrote:

var sel = document.create Element('select ');
var opt = document.create Element('option ');
sel.add(opt,nul l);

I thought the most widely supported method here was:

var sel = document.create Element('select ');
sel.options[sel.options.len gth] = new Option(...);
Maybe that's what you do in your library...

Not quite; that was a very simple example. Given:

function moveOption(from Sel,toSel,fromI ndex,toIndex) {
var opt = fromSel.options[fromIndex];
if (opt != null) // yes, this is an explicit test
toSel.add(opt,t oIndex);
}

According to the W3C spec, there's no reason this should
not work; but you may find it problematic in some browsers.
The library makes it work as expected.
[Caveat: I'm posting from home; this is from memory and untested.]
hj

[hj]

hj wrote:

Not quite; that was a very simple example. Given:

function moveOption(from Sel,toSel,fromI ndex,toIndex) {
var opt = fromSel.options[fromIndex];
if (opt != null) // yes, this is an explicit test
toSel.add(opt,t oIndex);
}

Um ... as I was saying ...
function moveOption(from Sel,toSel,fromI ndex,toIndex) {
var opt = fromSel.options[fromIndex];
if (opt != null) // yes, this is an explicit test
toSel.add(opt,t oSel.options[toIndex]);
}

hj

[RobG]

VK wrote:

RobG wrote:

I suppose suggesting Firefox is of no use? ;-)

Or if the Aqua-style is too precious to you ;-) you may consider Gecko
Camino:
<http://www.caminobrows er.org/>

I've tried Camino, but it's only at version 0.8.4 so while OK for home
use can't really be recommended to a corporate client.

Ooops!! Just checked Mozilla.org, Camino has now hit 1.0b1 - seems they
even got tabs to left-justify!!


Safary 1.x - 2.0 is a complete junk as browser. So is the Konqueror
used as the base for it.

Dunno, I find Safari fine for general web surfing. I like many of the
features, though its support for JavaScript and DOM is disappointing -
but I haven't tried the latest version yet. I'm trying to get OS X 10.4
on eBay but keep getting sniped!
[...]
--
Rob

[Thomas 'PointedEars' Lahn]

RobG wrote:

I've tried Camino, but it's only at version 0.8.4 so while OK for home
use can't really be recommended to a corporate client.

I have seen too many good 0.x versions of software to find this argument
justified.
PointedEars

[RobG]

Thomas 'PointedEars' Lahn wrote:

RobG wrote:

I've tried Camino, but it's only at version 0.8.4 so while OK for home
use can't really be recommended to a corporate client.

I have seen too many good 0.x versions of software to find this argument
justified.

I have deal with too many officious system adminstrators not to consider
it. ;-)

Anyhow, it seems 1.0 is (nearly) here.
--
Rob

[VK]

RobG wrote:

Dunno, I find Safari fine for general web surfing.

I did not say "It's a bad HTML 4.0 renderer". I said "It's a bad
browser". ;-)

Year 2005 these are very different kinds.

[hj]

hj wrote:

hj wrote:

Not quite; that was a very simple example. Given:

function moveOption(from Sel,toSel,fromI ndex,toIndex) {
var opt = fromSel.options[fromIndex];
if (opt != null) // yes, this is an explicit test
toSel.add(opt,t oIndex);
}

Um ... as I was saying ...
function moveOption(from Sel,toSel,fromI ndex,toIndex) {
var opt = fromSel.options[fromIndex];
if (opt != null) // yes, this is an explicit test
toSel.add(opt,t oSel.options[toIndex]);
}

or even (accounting for both per-spec and IE-specific behavior):

function moveOption(from Sel,toSel,fromI ndex,toIndex) {
var opt = fromSel.options[fromIndex];
if (opt != null) // yes, this is an explicit test
try {toSel.add(opt, toSel.options[toIndex])} catch(err) {
toSel.add(opt,t oIndex);
}
}

hj