Javascript error, not recognizing function... why?

Question

This is my code (in a firefox addon)

this.something_something = function (the_actual_url) {
    this.this_version = null;
    try {
        // Firefox 4 and later; Mozilla 2 and later
        Components.utils.import("resource://gre/modules/AddonManager.jsm");
        AddonManager.getAddonByID("[email protected]", function (addon) {
            this_version = addon.version;
        });
    }
    catch (ex) {
        // Firefox 3.6 and before; Mozilla 1.9.2 and before
        var em = Components.classes["@mozilla.org/extensions/manager;1"].getService(Components.interfaces.nsIExtensionManager);
        var addon = em.getItemForID("[email protected]");
        this_version = addon.version;
    }


    this.timervar = setTimeout(function () {
        this.get_plugin_version(this.this_version);
    }, 2000);
}

this.get_plugin_version = function (blah) {
    alert("aa:" + blah);
}

I get the error:

Error: this.get_plugin_version is not a function Source File: chrome://mf_monkey_project/content/overlay.js Line: 476

What am I doing wrong?

Sorry about the screwed up formatting, but i deleted the bulk of the code to fit here and it made the formatting all screwy.

user113716 · Accepted Answer · 2011-08-25 02:30:00Z

1

Because the setTimeout callback will be executed in the global context.

You can use the bind()^[docs] method to bind the desired context and argument for the callback.

this.timervar=setTimeout( this.get_plugin_version.bind(this, this.this_version),
                          2000 );

If you don't want the current value of this.this_version permanently bound as the first argument, then remove it from the .bind() call.

answered Aug 25, 2011 at 2:30

user113716

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6 Comments

Ryan Over a year ago

now I get Error: this.get_plugin_version is undefined Source File: chrome://mf_monkey_project/content/overlay.js Line: 476

user113716 Over a year ago

@Ryan: Then this in your something_something function is not the object you're expecting.

Ryan Over a year ago

Oops, no, I did an edit instead of copying your code.. it works, but gives me null as the version number :( any idea why?

user113716 Over a year ago

@Ryan: Because this.this_version = null;. If this_version is being updated within that 2000ms timer, then remove the this.this_version argument from the .bind() call. I updated my answer to reflect this.

Ryan Over a year ago

Now I am getting some funny numbers, like 12 or 2341 or 2343 etc... but not the version number :(

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