Javascript: settimeout problem

Question

When I start my script I have this:

var my_great_masterpiece = new function ()
{
 var self = this;

Then later in my script I have this:

 response_xml: function ()
 {
 if (self.http_request.readyState == 4)
 {
 if (self.http_request.status == 404 && countXmlUrl <= 3)
 {
 countXmlUrl++;
 self.realXmlUrl = xmlUrl[countXmlUrl];
 self.request_xml();
 }
 if (self.http_request.status == 200)
 {
 self.xmlDoc = self.http_request.responseXML;
 self.storage.setItem('domains_raw_xml', self.http_request.responseText);
 self.main.peter_save_data();
 self.timervar = setTimeout(function ()
 {
// ########### Below line gives the error #############################
 self.new_version_show_window();
 }, 2000);
 }
 }
 },
 new_version_show_window: function ()
 {
...
}

the error that I am getting is:

Error: self.new_version_show_window is not a function

What am I doing wrong?

Thanks!

• josh.trow: Have you tried moving the function definition for new_version_show_window above where it is called? Also, use a semicolon instead of a comma before new_version_show_window
• Felix Kling: How is the second part connected to the first part? Do you set the prototype?
• Felix Kling: @josh.trow: No, it seems to be an object literal. Properties are separated by comma.
• Jivings: @josh.trow - You are misunderstanding the code. There are no syntax errors that I can see.
• Felix Kling: You have to provide more information. We have to know where new_version_show_window is defined. Right now it could be everywhere...

Answer 1

It is unclear from your code where new_version_show_window is defined. Maybe you could explicitly define it on self:

self.new_version_show_window = function () {
 /* ... */
}

instead. Or you could define it in the local namespace and use it directly in the setTimeout call:

self.timervar = setTimeout(function () {
 new_version_show_window();
 }, 2000);

or simply:

self.timervar = setTimeout(new_version_show_window, 2000);

Because of closure, the variables declared in the outer function is also available in the inner function.

Edit

Thanks for posting the entire code. new_version_show_window is defined on this.main, so you must access it thusly:

self.timervar = setTimeout(function () {
 self.main.new_version_show_window();
 }, 2000);

• Felix Kling: If the (partial) object literal is used as prototype, then it should work. But we need more information...
• Magnar: Yes, you're right about that. However, since self closes over all the functions, it is basically a singleton - making little sense for a prototype.
• Felix Kling: @Ryan: As I said, we actually need the complete code. There is no way to tell what you did wrong because we don't know in which scope the second part is.
• Magnar: new_version_show_window is defined on this.main, so you have to call self.main.new_version_show_window();
• Ryan: That worked! Thanks guys! Don't know when JS got this complicated... I used to work with some simple stuff a couple of years back and am just getting back into it. Anonymous functions... encapsulated objects... never did/had that before and am quite lost. Would be in deep poop if it was not for SO and you wonderful people... thanks!

Answer 2

It could be that self is a reserved word in JavaScript [1]. This could be causing you some problems so try naming the variable something different to start with.

[1] http://www.quackit.com/javascript/javascript_reserved_words.cfm

• Felix Kling: @Jivings: Well, I can tell you that there is no problem using it in a browser context. Otherwise a lot of my code would be broken... It is definitely possible to define it as local variable in a function. There are no other predefined variables with which it could clash.
• Jivings: @Felix - Haha okay, tbh I think I've used it before also. I just didn't see anything else immediately wrong with the code.
• Magnar: Felix is right. It may be on those lists, but self causes no problems as a local variable at least. I've used it plenty without any issues.

Answer 3

This is a problem of scope. new_version_show_window is only in scope in the construct in which is it called ( apparently a jQuery AJAX function of some sort). It will only be available to my_great_masterpiece if you define it outside the limited scope in which it now exists.