Add jQuery to your Greasemonkey script

Greasemonkey is a Firefox add-on that lets you run JavaScript on web pages you specify. Using Greasemonkey you can improve and change the way websites look and behave (see examples of what is possible here). To learn more about it see it's official site, to learn how to include and write your own custom scripts (aka "user scripts") visit coder's manual.

Usually Greasemonkey scripts work with the DOM and jQuery is the best way to do that. So, no wonder you'll want to include jQuery into your custom scripts. Here are 3 ways to include jQuery library into your user script.

If you are targeting for Greasemonkey 0.8.0+ you can use @require. It runs once when the script is being installed, hence downloaded once. This is preferred and most efficient way to add jQuery.

// ==UserScript==
// @name     My jQuery Test
// @require  http://ajax.googleapis.com/ajax/libs/jquery/1.6.2/jquery.min.js
// ==/UserScript==

// Do your magic here
$(".ads").remove();

If you are developing for older versions of Greasemonkey you have 2 options. Either add the whole jQuery library code into your Greasemonkey script file or dynamically add a <script> tag to the page.

Adding jQuery library right in your custom script

// ==UserScript==
// @name     My jQuery Test
// ==/UserScript==

// include jQuery library
/*!
 * jQuery JavaScript Library v1.6.2
 * http://jquery.com/
 *
 * Copyright 2011, John Resig
 * Dual licensed under the MIT or GPL Version 2 licenses.
 * http://jquery.org/license
 *
 * Includes Sizzle.js
 * http://sizzlejs.com/
 * Copyright 2011, The Dojo Foundation
 * Released under the MIT, BSD, and GPL Licenses.
 *
 * Date: Thu Jun 30 14:16:56 2011 -0400
 */
(function(a,b){function cv(a){return f.isWindow(a)? ...

One more method to add jQuery

One more way to add jQuery is by attaching <script> tag to the document. You can read more about it and grab the code here.

Don't forget to check if jQuery is already loaded

if (unsafeWindow.jQuery === undefined) {
  // jQuery is NOT loaded
} else {
  // jQuery is already loaded
}

HTML: The difference between attribute and property

In this short post I will explain the difference between attributes and properties in HTML. The .prop() function introduced in jQuery 1.6 raised a lot of questions about the difference and I hope this post will help you to understand it.

What is an attribute?

Attributes carry additional information about an HTML element and come in name=”value” pairs. Example: <div class=”my-class”></div>. Here we have a div tag and it has a class attribute with a value of my-class.

What is a property?

Property is a representation of an attribute in the HTML DOM tree. So the attribute in the example above would have a property named className with a value of my-class.

Our DIV node
 |- nodeName = "DIV"
 |- className = "my-class"
 |- style
   |- ...
 |- ...

What is the difference between attribute and property?

Attributes are in your HTML text document/file, whereas properties are in HTML DOM tree. This means that attributes do not change and always carry initial (default) values. However, HTML properties can change, for example when user checks a checkbox, inputs text to textarea or uses JavaScript to change the property value.

Here is a visual representation:

HTML                          DOM
<input value="default" />     value = default



----------------
Current values:
Attribute: "default"          Property:  "default"

Assume user inputs his name "Joe" into the inputbox. Here are what attribute and property values of an element will be.

HTML                          DOM
<input value="default" />     value = Joe



----------------
Current values:
Attribute: "default"          Property:  "Joe"

As you can see, only element’s property is changed, because it is in the DOM and dynamic. But element’s attribute is in HTML text and can not be changed!

I hope this helps to understand the difference between attributes and properties. If you have any questions please leave them on jQueryHowto Facebook page.

Also, stay tuned for the next post about the difference between jQuery.attr() and jQuery.prop() and when to use one over another.

Check if a language file is loaded for jQuery Globalization plugin

Recently, I wrote my first jQuery Globalization plugin introductory post. I mentioned that I will write a tutorial for Globalization plugin and I am. While writing the tutorial I thought I’ll write one of my short Friday jQuery tips.

In this post you will learn how to check if a specific jQuery Globalization plugin language file is loaded or not. Globalization plugin saves localization data and all information in jQuery.cultures object. By default English language is added. So if you add "Inuktitut" language (code iu) the jQuery.cultures object will be extended and will have jQuery.cultures.iu object in it.

So to check if particular language file is loaded all we need to do is to check if jQuery.cultures.langCode is defined. Here is an example:

if($.cultures.iu){
    // Inuktitut jquery.glob.iu.js lang file is loaded
}else {
    // Inuktitut language is not loaded, load it here
}

Some cultures have different alphabet, so they will have that appended in their language and culture names. For example Inuktitut has Syllabics (iu-Cans) and Latin alphabets (iu-Latn), So you will not be able to check the file existence with the code above. Here is a syntax to do it:

if($.cultures.iu-Latin){
    // Will not work
}

// Better way to check if the lang file is loaded
if($.cultures["iu-Latn"]){
    // Inuktitut jquery.glob.iu-Latn.js lang file is loaded
}else {
    // Inuktitut language is not loaded, load it here
}

JavaScript to detect iPad visitors

This post gives you a short JavaScript function to detect your iPad users. Without any further ado, a javascript code to detect iPad users:

function isiPad(){
    return (navigator.platform.indexOf("iPad") != -1);
}

You can also detect browser version and some other stuff by parsing user agent string. Here is an iPad Safari’s user agent string for your reference:

Mozilla/5.0 (iPad; U; CPU OS 3_2 like Mac OS X; en-us) AppleWebKit/531.21.10 (KHTML, like Gecko) Version/4.0.4 Mobile/7B334b Safari/531.21.10

Recently a friend of mine got himself an iPad and I couldn’t not notice how his internet browsing device preferences are changing (PC & iPad). More and more people are using hand held devices namely iPad to browse the internet. So it’s about time to show your iPad visitors some love and display your website designed specifically for iPad.

Let’s see how to do this. There are two way:

1. Redirect iPad visitors
2. Apply different CSS file for iPad users

Most of the posts on the internet related to iPad user detection are suggesting and showing you how to redirect (including myself in my previous iPhone & iPod detection post). However, I would recommend the second option, applying different CSS file.

You can apply the same technique described in applying different styling for javascript enabled browser with CSS post and apply different CSS rules for iPad visitors.

Sidenote: If you decide to redirect iPad users rather than apply different CSS style rules, than I would recommend using server side detection and redirection. You can see an example PHP code by David Walsh.

jQuery Globalization plugin — jquery.glob.js

This is the first post of a series that are dedicated to jQuery’s new Microsoft contributed Globalization plugin or shortly jquery.glob.js. In this first post I will try to cover the very basics like library licensing, “the good & the bad” and some thoughts on how it could be improved (IMO).

I will be post some jQuery globalization plugin tutorials in coming days, so bare with me.

Before we jump into licensing and support issues, first things are first. What’s up with the name? It’s confusing! When did we start calling localization (l10n) a globalization?! I haven’t seen any g12n abbreviations lately, have you? When I first came across it, I thought it was some wicked jQuery solution to "global variables are evil" idea or solution to some other problem that I am not even familiar with :) Don’t you agree, it’s confusing a bit.

So, there you go. One little improvement: "Don’t confuse, rename it!"

Before we talk about the jQuery globalization plugin license, let me mention that this plugin is now officially supported by jQuery Project. Which means that it will be under continues improvement by jQuery core team and will be compatible with the future jQuery and jQuery UI releases. Also globalization plugin will become a part of the jQuery UI project.

jQuery Project officially supports jQuery Globalization plugin.

Now, the legal stuff – the license. Because jQuery project accepted the globalization plugin as officially supported (and of course because Microsoft agreed to its terms) jQuery Globalization plugin is distributed under the same license as core jQuery.js. So you are safe to do pretty much anything.

jQuery Globalization plugin is licensed under the same non-restrictive terms as the core jQuery.js

After playing with the plugin for a while I realized that it does not do any DOM manipulations and you certainly don’t expect any animations. So what’s the point of having it as jQuery plugin and not a general JavaScript globalization/localization library? This way a larger community could benefit from it. I guess it was more of marketing decision rather than technical.

JavaScript library alternative to globalization plugin would be nice.

To be honest, JavaScript and jQuery community had a lack of localization libraries and jQuery Globalization plugin with over 350 localizations is a great solution. Surely, plugin’s exposed function names and namespacing could be improved, and most probably will be, but we’ll talk about it in our next “jQuery Globalization plugin tutorial” post. Stay tuned…