onkeydown event on document element

[b.dam]

I'm trying the following:

function grid() {
this._el = document.create Element("TABLE" );

var self = this;
document.addEve ntListener("onk eydown", function(event)
{self.gridKeyDo wn(event);}, false);
}

grid.prototype. gridKeyDown = function(event) {
//some code
}

var datagrid = new grid();
the addEventListene r doesn't get added, the gridKeyDown method never
gets executed. Can I add onkeydown to the document object? Is there a
good reference about mozilla dom?

[Random]

b.***@gmx.net wrote:

I'm trying the following:

function grid() {
this._el = document.create Element("TABLE" );

var self = this;
document.addEve ntListener("onk eydown", function(event)
{self.gridKeyDo wn(event);}, false);
}

grid.prototype. gridKeyDown = function(event) {
//some code
}

var datagrid = new grid();
the addEventListene r doesn't get added, the gridKeyDown method never
gets executed. Can I add onkeydown to the document object? Is there a
good reference about mozilla dom?
Other discussions are currently going regarding event handling and how
to dynamically cause it.

The simplest way to do it is also the most cross-compatible:

document.onkeyd own = function ( event ) {
event = event || window.event;
// figure out which of your grid objects it applies to
// then fire your gridKeyDown function thereon
myGrid.gridKeyD own( event );
}
// the constructor
function grid( ) {
this._el = document.create Element("TABLE" );
return this;
}

// note that you need to define the prototype before you may
// change it
grid.prototype = {
gridKeyDown: function (event) {
//some code
}
}

var datagrid = new grid();

---------

You do not need to attach the onKeyDown handler every time you create a
grid because the handler will be handling keyDown events for the entire
document, not for each individual grid object.
var self = this;
document.addEve ntListener("onk eydown", function(event)
{self.gridKeyDo wn(event);}, false);

If you do it this way, self will not be defined by the time onkeydown
handler is called, because onkeydown will be called outside of the
scope of the grid object constructor -- which is the desired behavior.

[VK]

addEventListene r("k*eydown", ...

All event names in addEventListene r are w/o "on", but obj.onkeydown
(with "on").
Obviously some English grammar lover (and end-developers hatter) is
working in the Mozilla team :-)

"self" is a window property reffering to the current window.
So
var self = this;
equal to
var windows.self = windows.self;
which is wrong and pointless.

Make these changes and come back ;-)

[Random]

Random wrote:

If you do it this way, self will not be defined by the time onkeydown
handler is called, because onkeydown will be called outside of the
scope of the grid object constructor -- which is the desired behavior.
When he should have written: If you do it this way, self will not be defined as you expect by the
time onkeydown handlers is called, because onkeydown will be called
outside of the scope of the grid object constructor -- which is the
desired behavior. Instead, self [as VK pointed out] will be a
reference to the current window.

[b.dam]

Thanks for the replies.

I agree that the 'var self = this' seems a little pointless, but it
works, in both IE and mozilla. Try it for yourself.
Anyway, I agree with Random that his example is the most simple.
Problem with this is that I need to keep track of all my grids in a
global array or something, ugly. I solve cross-browser issues with this
mozilla only function:

HTMLElement.pro totype.attachEv ent = function(sType, fHandler) {
sType = sType.replace(" on", "");
this.addEventLi stener(sType, fHandler, false);
}

Now I can use attachEvent on IE and mozilla. This doesn't work on the
document element however, and document.protot ype isn't allowed. My
javascript console sais: "document.proto type has no properties". Any
suggestions?

[b.dam]

Never mind, I needed to use Document.protot ype, with a capital D

I've got it working now, tnx!

[Random]

b.***@gmx.net wrote:

Thanks for the replies.

I agree that the 'var self = this' seems a little pointless, but it
works, in both IE and mozilla. Try it for yourself.
Anyway, I agree with Random that his example is the most simple.
Problem with this is that I need to keep track of all my grids in a
global array or something, ugly. I solve cross-browser issues with this
mozilla only function:

HTMLElement.pro totype.attachEv ent = function(sType, fHandler) {
sType = sType.replace(" on", "");
this.addEventLi stener(sType, fHandler, false);
}

Now I can use attachEvent on IE and mozilla. This doesn't work on the
document element however, and document.protot ype isn't allowed. My
javascript console sais: "document.proto type has no properties". Any
suggestions?

I don't believe the document object has a prototype. Did you plan on
creating new document objects inside the current window, without
replacing the current document? If not, such a prototype would be
useless anyway.

Try this, if you're intent on using attachEvent emulation:
document.attach Event = HTMLElement.pro totype.attachEv ent;

[Random]

b.***@gmx.net wrote:

Never mind, I needed to use Document.protot ype, with a capital D

I've got it working now, tnx!

....

nevermind, then.

Document, huh...

ideas...

[Richard Cornford]

Random wrote:

Random wrote:

If you do it this way, self will not be defined by the
time onkeydown handler is called, because onkeydown will
be called outside of the scope of the grid object
constructor -- which is the desired behavior.

When he should have written:

If you do it this way, self will not be defined as you
expect by the time onkeydown handlers is called, because
onkeydown will be called outside of the scope of the grid
object constructor -- which is the desired behavior.
Instead, self [as VK pointed out] will be a reference to
the current window.

Don't pay any attention to what VK says. He has a conception of
javascript and browser scripting that differs considerably form reality.
Instead read:-

<URL: http://jibbering.com/faq/faq_notes/closures.html >

- and find out what it means to be using a lexically scoped functional
programming language.

Richard.

[Thomas 'PointedEars' Lahn]

b.***@gmx.net wrote:

Never mind, I needed to use Document.protot ype, with a capital D

This only works, i.e. does not result in a script error, if there is
a Document constructor, AFAIK by default restricted to the Gecko DOM.
PointedEars
--
Die erste Gunst ist Gunst, die zweite schon Verpflichtung.
-- Chinesisches Sprichwort