Is it possible?

**Michael Winter** · Jul 23 '05, 08:33 PM

Re: Is it possible?

On 07/06/2005 12:26, Fabri wrote:
[color=blue]
> Is it possible, as IE does in Windows Update, to ask onbeforeunload if
> the user want really close window (or tab) clicking on close (X) of the
> window?[/color]

Yes.

[snip]
[color=blue]
> window.onbefore unload = function(){
> if (confirm('Reall y want to go away?')){
> this.close();
> } else {
> return null
> }
> }[/color]

You're expected to return a string that contains the prompt to be
displayed. IE handles the confirmation and closing itself.

[snip]

Mike

--
Michael Winter
Replace ".invalid" with ".uk" to reply by e-mail.

VK · Jul 23 '05, 08:33 PM

Re: Is it possible?

All you need to do is to *cancel* the windowClose event. This will trig
the internal confirmation dialog (so you don't need and you cannot set
it up):

<script type="text/javascript">
window.onbefore unload = function(e){
if (e != null) {
e.preventDefaul t();
}
else {
event.returnVal ue = false;
}
}
</script>

**Fabri** · Jul 23 '05, 08:33 PM

Re: Is it possible?

Michael Winter wrote:
[color=blue][color=green]
>> window.onbefore unload = function(){
>> if (confirm('Reall y want to go away?')){
>> this.close();
>> } else {
>> return null
>> }
>> }[/color]
>
>
> You're expected to return a string that contains the prompt to be
> displayed. IE handles the confirmation and closing itself.[/color]

Sorry Mike, I don't understand, u mean perhaps:

<script type="text/javascript">
window.onbefore unload = function(){
var retVal = confirm('Really want to go away?');
if (retVal){
this.close();
} else {
return null
}
}
</script>

? or not?

Can u please give me a working example?

Regards.

--
Fabri
("Sono più di 30 punti...ma è come se fossere 8 o 9....")

**Fabri** · Jul 23 '05, 08:33 PM

Re: Is it possible?

VK wrote:
....

[snip]

Thx :-)

--
Fabri
("Sono più di 30 punti...ma è come se fossere 8 o 9....")

**Michael Winter** · Jul 23 '05, 08:33 PM

Re: Is it possible?

On 07/06/2005 12:52, Fabri wrote:
[color=blue]
> Michael Winter wrote:
>[color=green]
>> You're expected to return a string that contains the prompt to be
>> displayed. [...][/color]
>
> Sorry Mike, I don't understand[/color]

[snip]
[color=blue]
> Can u please give me a working example?[/color]

Microsoft's documentation provides one, but...

As an attribute:

<body onbeforeunload= "return 'This is the prompt text.';">

As an event property assignment:

window.onbefore unload = function() {
return 'This is the prompt text.';
};

The documentation uses the proprietary event.returnVal ue property
instead of a return statement, but the result is the same.

Mike

--
Michael Winter
Replace ".invalid" with ".uk" to reply by e-mail.

**Duncan Booth** · Jul 23 '05, 08:33 PM

Re: Is it possible?

Michael Winter wrote:
[color=blue]
> As an event property assignment:
>
> window.onbefore unload = function() {
> return 'This is the prompt text.';
> };
>
> The documentation uses the proprietary event.returnVal ue property
> instead of a return statement, but the result is the same.[/color]

Not quite. The return statement won't have the desired effect on IE, and
event.returnVal ue won't have any effect on Mozilla. To write code which
works on both you have to use both.

window.onbefore unload = function(event) {
var msg = 'This is the prompt text.';
if (!event) event = window.event;
if (event) event.returnVal ue = msg;
return msg;
};

Also note that if you use Mozilla's addEventHandler method to add handler
function, Mozilla will ignore the return value totally (so the function
gets called, but nothing you can do will make it pop up the warning box).

Here's a longer example (but still self-contained) which implements a
warning box whenever you try to navigate away from a page with a modified
form.

The original is at
http://codespeak.net/svn/kupu/trunk/...eforeunload.js,
documentation at
http://codespeak.net/svn/kupu/trunk/...FOREUNLOAD.txt, license at
http://codespeak.net/svn/kupu/trunk/...oc/LICENSE.txt. Add a call to
window.onbefore unload.tool.add Forms() to enable checking.

/* BeforeUnload form processing */
if (!window.before unload) (function() {
var BeforeUnloadHan dler = function() {
var self = this;

this.message = "Your form has not been saved. All changes you have
made will be lost";
if (window._) {
this.message = _("Your form has not been saved. All changes you
have made will be lost");
};
this.forms = [];
this.chkId = [];
this.chkType = new this.CheckType( );
this.handlers = [this.isAnyFormC hanged];
this.submitting = false;

this.execute = function(event) {
if (self.submittin g) return;
if (!event) event = window.event;

for (var i = 0; i < self.handlers.l ength; i++) {
var fn = self.handlers[i];
var message = message || fn.apply(self);
}
if (message===true ) message = self.message;
if (message===fals e) message = undefined;
if (event) event.returnVal ue = message;
return message;
}
this.execute.to ol = this;
}
var Class = BeforeUnloadHan dler.prototype;

// form checking code
Class.isAnyForm Changed = function() {
for (var i=0; i < this.forms.leng th; i++) {
var form = this.forms[i];
if (this.isElement Changed(form)) {
return true;
}
}
return false;
}
Class.addHandle r = function(fn) {
this.handlers.p ush(fn);
}
Class.onsubmit = function() {
var tool = window.onbefore unload && window.onbefore unload.tool;
tool.submitting = true;
}
Class.addForm = function(form) {
for (var i = 0; i < this.forms.leng th; i++) {
if (this.forms[i]==form) return;
}
this.forms.push (form);
form.onsubmit = this.onsubmit;
var elements = form.getElement sByTagName('inp ut');
for (var j = 0; j < elements.length ; j++) {
var ele = elements[j];
if (ele.type=='hid den') {
ele.setAttribut e('originalValu e', ele.defaultValu e);
}
}
}
Class.addForms = function() {
for (var i = 0; i < arguments.lengt h; i++) {
var element = arguments[i];
if (!element) continue;
if (element.tagNam e=='FORM') {
this.addForm(el ement);
}
else {
var forms = element.getElem entsByTagName(' form');
for (var j = 0; j < forms.length; j++) {
this.addForm(fo rms[j]);
}
}
}
}
Class.removeFor ms = function() {
for (var i = 0; i < arguments.lengt h; i++) {
var element = arguments[i];
if (!element) continue;
if (element.tagNam e=='FORM') {
for (var j = 0; j < arguments.lengt h; j++) {
if (this.forms[j] == element) {
this.forms.spli ce(j--, 1);
element.onsubmi t=null;
}
}
} else {
var forms = element.getElem entsByTagName(' form');
for (var j = 0; j < forms.length; j++) {
this.removeForm s(forms[j]);
}
}
}
}

Class.CheckType = function() {};
var c = Class.CheckType .prototype;
c.checkbox = c.radio = function(ele) {
return ele.checked != ele.defaultChec ked;
}
c.password = c.textarea = c.text = function(ele) {
return ele.value != ele.defaultValu e;
}
// hidden: cannot tell on Mozilla without special treatment
c.hidden = function(ele) {
var orig = ele.getAttribut e("originalValu e");
return orig && (ele.value != orig);
}

c['select-one'] = function(ele) {
for (var i=0 ; i < ele.length; i++) {
var opt = ele.options[i];
if ( opt.selected != opt.defaultSele cted) {
if (i===0 && opt.selected) continue; /* maybe no default */
return true;
}
}
return false;
}

c['select-multiple'] = function(ele) {
for (var i=0 ; i < ele.length; i++) {
var opt = ele.options[i];
if ( opt.selected != opt.defaultSele cted) {
return true;
}
}
return false;
}

Class.chk_form = function(form) {
var elements = form.elements;
for (var i=0; i < elements.length ; i++ ) {
var element = elements[i];
if (this.isElement Changed(element )) {
return true;
}
}
return false;
}

Class.isElement Changed = function(ele) {
var method = ele.id && this.chkId[ele.id];
if (!method && ele.type && ele.name)
method = this.chkType[ele.type];
if (!method && ele.tagName)
method = this['chk_'+ele.tagN ame.toLowerCase ()];

return method? method.apply(th is, [ele]) : false;
};

window.onbefore unload = new BeforeUnloadHan dler().execute;
})();

**Michael Winter** · Jul 23 '05, 08:33 PM

Re: Is it possible?

On 07/06/2005 13:48, Duncan Booth wrote:
[color=blue]
> Michael Winter wrote:[/color]

[snip]
[color=blue][color=green]
>> The documentation uses the proprietary event.returnVal ue property
>> instead of a return statement, but the result is the same.[/color]
>
> Not quite. [...] To write code which works on both you have to use both.[/color]

No you don't. IE accepts either form, but the documentation just happens
to use the returnValue property.

[snip]

Mike

--
Michael Winter
Replace ".invalid" with ".uk" to reply by e-mail.

**Duncan Booth** · Jul 23 '05, 08:33 PM

Re: Is it possible?

Michael Winter wrote:
[color=blue]
> On 07/06/2005 13:48, Duncan Booth wrote:
>[color=green]
>> Michael Winter wrote:[/color]
>
> [snip]
>[color=green][color=darkred]
>>> The documentation uses the proprietary event.returnVal ue property
>>> instead of a return statement, but the result is the same.[/color]
>>
>> Not quite. [...] To write code which works on both you have to use both.[/color]
>
> No you don't. IE accepts either form, but the documentation just happens
> to use the returnValue property.
>
> [snip][/color]

Yes, you are correct.

I mis-remembered, or else I spent so long wrestling with the event on
Mozilla that I probably just ended up confusing myself.

Is it possible?

Is it possible?

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