Share your knowledge and create a knowledgebase.
Share your knowledge and create a knowledgebase.
There are literally over a hundred of JavaScript frameworks out there that make writing complex client-side code significantly easier. If you’re in the market for a powerful, relatively lightweight, and customizable JavaScript framework, MooTools is worth checking out.
To help you get on your way to developing highly-interactive web applications using MooTools, here’s 20 tutorials and working examples that’s worth a read.
The Mootorial at //clientside is a comprehensive, practical tutorial on the MooTools framework. The tutorial allows you to execute the sample code either by Firebug or the website’s built-in console.
Here’s an excellent screencast that introduces the MooTools framework. It covers the basics such as the concept of chaining, customizing MooTools to your needs, and where to find documentation for MooTools code.
Beauty By Design provides a nine-part video series on improving user interaction using JavaScript (primarily MooTools). A couple of topics covered in the lessons include: using mooTabs, creating sliding sub menus, and using Fx.styles to control font size.
One of the most powerful features of MooTools (as well as other frameworks/libraries like jQuery and Prototype) is the ability to easily select page objects for you to work on. This tutorial covers the basics of selectors in MooTools: $(), $$(), $E(), and $ES() functions.
This tutorial is an entry-level introduction on working with classes in MooTools. The tutorial works with a hypothetical scenario (buying a car from a car store) to illustrate the concept of classes. The last section of the article discusses the differences of MooTools and script.aculo.us classes.
MooTools’ Ajax/XHR classes provides developers a much simpler way of working with XMLHTTPRequests by reducing the amount of code you have to write and by handling browser differences for you. This tutorial talks about the Ajax and XHR classes in brief.
This article delves into the use, extension, and capabilities of the Ajax class in MooTools. It discusses chaining Ajax requests and events, and how you can extend the Ajax class for your needs (also applicable to other MooTools classes).
Getting started with MooTools is easy, and it won’t be long until you can create wonderful effects and increase user interactivity in your web pages. To help you become a MooTools master, here’s a checklist of common coding mistakes and its corresponding correct usage.
This is a follow-up article from the one above, focusing more on MooTools syntax usage. Examples involve using shorter code for selection of objects, shorthand for the Ajax class, and creating new elements.
Here’s an excellent introduction to using JSON with MooTools to provide server-side interaction to your web applications. Topics covered include converting a JSON string into a JavaScript object and vice versa.
This article explains how to take advantage of MooTools’ powerful Hash.Cookie API to make working with complex cookie utilization a cinch. The example showcases a working example of how you can store the number of times a user visits a page.
Chaining is beneficial for several reasons including the ability to sequentially execute events (”in a chain”) as well as reduce the number of lines of code you have to write. If you’re wondering about the “who, what, where” of chaining in MooTools, check out this brief but informative tutorial.
Learn how to protect your public web forms from spam and SQL injections with this tutorial on how MooTools can be used to make safer public web forms.
Create a navigation area that smoothly scrolls left or right depending on where you hover your mouse.
Check out this nifty tutorial on how to build a Facebook-inspired set of slider controls that manipulate the opacity, width, and height of an image.
In this tutorial, you’ll learn how to make page elements flash. It’s an effective way of drawing attention to a particular section of a web page or alerting users of status changes.
Here’s a tutorial on how to display messages that fades in after the user clicks on the submit button. It’s designed for use with web forms, but it can be modified into similar applications.
This tutorial shows you how to build a navigation menu that slides up and down smoothly using MooTools. The article also covers how to make a similar effect using plain JavaScript.
Here’s an excellent step-by-step tutorial on how to make a content area that slides left-to-right at set intervals – great for slideshows.
This is a two-part series that goes over how to make your web forms fancier. The first part shows you how to add animated field highlighting and how to display instructions to users. In the second part, you’ll step it up a notch by adding live comment previewing and auto-resizing of text areas.
Javascript applications are still one of the most complex issues when it comes to web-development. Many tools and applications could make your developing life pretty fast and simple. Today we wanted to share with you a wide range of tools and applications that could really help you build, test and debug Javascript and Ajax applications. Let us know your experience with the tools listed here or others that are not.
1-Roar - Notifications (v1.0) Roar is a notification widget that streamlines incoming messages, such as updates or errors, without distracting the user from their browser experience or breaking their work-flow by displaying obtrusive alerts.
4-Google AJAX Language API With the AJAX Language API, you can translate and detect the language of blocks of text within a webpage using only Javascript. The language API is designed to be simple and easy to use to translate and detect languages on the fly when offline translations are not available.
7- SproutCoreSproutCore is a framework for building applications in JavaScript with remarkably little amounts of code. It can help you build full “thick” client applications in the web browser that can create and modify data, often completely independent of your web server, communicating with your server via Ajax only when they need to save or load data.
9-Jaxer Jaxer is an Ajax server. HTML, JavaScript, and CSS are native to Jaxer, as are XMLHttpRequests, JSON, DOM scripting, etc. And as a server it offers access to databases, files, and networking, as well as logging, process management, scalability, security, integration APIs, and extensibility.
20- Greasemonkey Greasemonkey is a Firefox extension that allows you to customize the way web pages look and function. You can use it to make a web site more readable or more usable. You can fix rendering bugs that the site owner can’t be bothered to fix themselves.
Generally, we are familiar with setting the target of a link to "_new" to spawn a secondary browser; there are other interesting ways of opening/launching of windows too using JavaScript.
JavaScript can help load 3 kinds of windows:
-Regular secondary window
-Modal window
-DHTML window
<script>
function loadwindow(){
window.open("http://www.hurricanesoftwares.com","","width=500,height=400,status=1")
}
</script>
<form><input type="button" onClick="loadwindow()" value="Load Window"></form>
"status=1" tells the method to display the status bar; "1" is the computer equivalent of "yes"
Manipulating the window
There are various methods available to move, close, resize or reload the window.
-window.location.reload() //reloads window
-window.close() //closes window
-window.moveTo(x,y) //moves window to specified location
-window.moveBy(x,y) //moves window by specified offset
-window.resizeTo(x,y) //resizes window to specified dimensions
-window.resizeBy(x,y) //resizes window by specified amount
To use these methods on the current window, simply call them as is on the page. You can also use them on the opened window, by following these two steps:
Step 1: When opening a window, assign a variable to it:
mywin=window.open("http://www.hurricanesoftwares.com")
Step 1: Use this variable to reference the opened window, then apply the desired method on it:
mywin.location.reload //reload mywin
mywin.moveTo(0,0) //positions window at upper left corner of monitor
Ok, getting back on track…
Modal Window
Modal windows are a fun Internet Explorer specific feature. The window sits "focused" on the page until the user clicks on the close button. The window does not go into the background no matter what (for example, clicking on the main window).
window.showModalDialog("http://www.hurricanesoftwares.com","","dialogWidth:500px;dialogHeight:500px")
Notice how I use dialogWidth and dialogHeight to specify the window’s dimension. You also need to specify the unit, which in this case I use px.
DHTML Window
A new type of window is emerging, one I think is worth mentioning. It is now possible to recreate the entire window interface through JavaScript and DHTML. The result is a less intrusive, inline popup window.
JavaScript, aka Mocha, aka LiveScript, aka JScript, aka ECMAScript, is one of the world’s most popular programming languages. Virtually every personal computer in the world has at least one JavaScript interpreter installed on it and in active use. JavaScript’s popularity is due entirely to its role as the scripting language of the WWW.
Despite its popularity, few know that JavaScript is a very nice dynamic object-oriented general-purpose programming language. How can this be a secret? Why is this language so misunderstood?
The article by Douglas in Crockford.com clearly shows the lack of knowledge or misunderstanding people have about JavaScript.
I do believe that there can be several reasons why people haven’t taken the JavaScript as strongly as they took other server side languages like PHP, Ruby etc though JS is used in almost all the websites.
The problem of JavaScript is that for years there have been no decent debugging tools. Because of that it takes a huge amount of effort just to write stable code. At the end the day a programmer is so frustrated with JavaScript that at the point he’s not interested in looking into ‘cool’ features.
I think it’s libraries like Prototype, script.aculo.us, etc. that have breathed new life in to JavaScript. At any rate, they caused me to take a second look at the language and realize its power and usefulness.
I would highly recommend Dojo, http://dojotoolkit.org/, to anyone thinking of doing any type of semi-complex javascript or AJAX. It also has scads of utility scripts that, in the past, I have found myself writing over and over again.
Though the docs are currently sparse, there a large number of test cases that give great examples and the mailing list is incredibly helpful. Dojo is also great example of how to properly write OO javascript. They even use a package naming structure similar to Java to help organize code.
I have also found few people in my vicinity who thinks that COBOL is most misunderstood programming language.
JavaScript is a scripting language most often used for client-side web development. It was the originating dialect of the ECMAScript standard. As such, it is a dynamic, weakly typed, prototype-based language with first-class functions.
JavaScript was influenced by many languages and was designed to have a similar look to Java, but be easier for non-programmers to work with. The language is best known for its use in websites (as client-side JavaScript), but is also used to enable scripting access to objects embedded in other applications.
Despite the name, JavaScript is essentially unrelated to the Java programming language, though both have a common debt to C syntax, and JavaScript copies many Java names and naming conventions. The language was renamed from LiveScript in a co-marketing deal between Netscape and Sun in exchange for Netscape bundling Sun’s Java runtime with their browser, which was dominant at the time. The key design principles within JavaScript are inherited from the Self programming language.
"JavaScript" is a trademark of Sun Microsystems. It was used under license for technology invented and implemented by Netscape Communications and current entities such as the Mozilla Foundation.
avaScript was originally developed by Brendan Eich of Netscape under the name Mocha, later LiveScript, and finally renamed to JavaScript. The change of name from LiveScript to JavaScript roughly coincided with Netscape adding support for Java technology in its Netscape Navigator web browser. JavaScript was first introduced and deployed in the Netscape browser version 2.0B3 in December of 1995. The naming has caused confusion, giving the impression that the language is a spinoff of Java and has been characterized by many as a marketing ploy by Netscape to give JavaScript the cachet of what was then the hot new web-programming language.
To avoid trademark issues, Microsoft named its dialect of the language JScript. JScript was first supported in Internet Explorer version 3.0, released in August 1996 and included Y2K compliant date functions, unlike those based on java.util.Date in JavaScript at the time.
Netscape submitted JavaScript to Ecma International for standardization resulting in the standardized version named ECMAScript.
Structured programming
JavaScript supports all the structured programming syntax in C, e.g. if statement, while loops, switch statement, etc. One exception is scoping: JavaScript supports function-level scoping, but not block-level scoping.
Dynamic programming
dynamic typing
As in most scripting languages, types are associated with values, not variables. For example, a variable x could be bound to a number, then later rebound to a string. JavaScript supports various ways to test the type of an object, including duck typing.
objects as associative arrays
JavaScript is heavily object-based. Objects are associative arrays, such that object property names are associative array keys. obj.x = 10 and obj["x"] = 10 are equivalent, the dot notation being merely syntactic sugar. Properties and their values can be added, changed, or deleted at run-time.
interpreted
Conforming JavaScript engines must be able to interpret (as opposed to compile) source code. This allows JavaScript to include an eval function.
Function-level programming
first-class functions
Functions are first-class; they are objects themselves. As such, they have properties and can be passed around and interacted with like any other object.
inner functions and closures
Inner functions (functions defined within other functions) are created each time the outer function is invoked, and variables of the outer functions for that invocation continue to exist as long as the inner functions still exist, even if that invocation is finished (e.g. if the inner function was returned) — this is the mechanism behind closures within JavaScript.
Prototype-based
prototypes
JavaScript uses prototypes instead of classes for defining object properties, including methods, and inheritance. It is possible to simulate many class-based features with prototypes in JavaScript.
functions as object constructors
Functions double as object constructors along with their typical role. Prefixing a function call with new creates a new object and calls that function with its local this keyword bound to that object. The function’s prototype property determines the new object’s prototype.
functions as methods
Unlike many object-oriented languages, there is no distinction between a function definition and a method definition. Rather, the distinction occurs during function calling; a function can be called as a method. When a function is invoked as a method of an object, the function’s local this keyword is bound to that object.
Others
run-time environment
JavaScript typically relies on a run-time environment (e.g. in a web browser) to provide objects and methods by which scripts can interact with "the outside world". (This is not a language feature per se, but it is common in most JavaScript implementations.)
variadic functions
An indefinite number of parameters can be passed to a function. The function can both access them through formal parameters and the local arguments object.
regular expressions
JavaScript also supports regular expressions in a manner similar to Perl, which provide a concise and powerful syntax for text manipulation that is more sophisticated than the built-in string functions.
The primary use of JavaScript is to write functions that are embedded in or included from HTML pages and interact with the Document Object Model (DOM) of the page. Some simple examples of this usage are:
* Opening or popping up a new window with programmatic control over the size, position and ‘look’ of the new window (i.e. whether the menus, toolbars, etc. are visible).
* Validation of web form input values to make sure that they will be accepted before they are submitted to the server.
* Changing images as the mouse cursor moves over them: This effect is often used to draw the user’s attention to important links displayed as graphical elements.
Because JavaScript code can run locally in a user’s browser (rather than on a remote server), it can respond to user actions quickly, making an application feel more responsive. Furthermore, JavaScript code can detect user actions which HTML alone cannot, such as individual keystrokes. Applications such as Gmail take advantage of this: much of the user-interface logic is written in JavaScript, and JavaScript dispatches requests for information (such as the content of an e-mail message) to the server. The wider trend of Ajax programming similarly exploits this strength.
A JavaScript engine (also known as JavaScript interpreter or JavaScript implementation) is an interpreter that interprets JavaScript source code and executes the script accordingly. The first ever JavaScript engine was created by Brendan Eich at Netscape Communications Corporation, for the Netscape Navigator web browser. The engine, code named SpiderMonkey, is implemented in C. It has since been updated (in JavaScript 1.5) to conform to ECMA-262 Edition 3. The Rhino engine, created primarily by Norris Boyd (also at Netscape) is a JavaScript implementation in Java. Like SpiderMonkey, Rhino is ECMA-262 Edition 3 compliant.
By far, the most common host environment for JavaScript is a web browser. Web browsers typically use the public API to create "host objects" responsible for reflecting the DOM into JavaScript. The web server is another common application of the engine. A JavaScript webserver would expose host objects representing a HTTP request and response objects, which a JavaScript program could then manipulate to dynamically generate web pages.
The DOM interfaces for manipulating Web pages are not part of the ECMAScript standard, or of JavaScript itself. Officially, they are defined by a separate standardization effort by the W3C; in practice, browser implementations differ from the standards and from each other, and not all browsers execute JavaScript.
To deal with these differences, JavaScript authors can attempt to write standards-compliant code which will also be executed correctly by most browsers; failing that, they can write code that checks for the presence of certain browser features and behaves differently if they are not available. In some cases, two browsers may both implement a feature but with different behavior, and authors may find it practical to detect what browser is running and change their script’s behavior to match. Programmers may also use libraries or toolkits which take browser differences into account.
Furthermore, scripts will not work for all users. For example, a user may:
* use an old or rare browser with incomplete or unusual DOM support,
* use a PDA or mobile phone browser which cannot execute JavaScript,
* have JavaScript execution disabled as a security precaution,
* or be visually or otherwise disabled and use a speech browser
To support these users, Web authors can try to create pages which degrade gracefully on user agents (browsers) which do not support the page’s JavaScript.
Security
JavaScript and the DOM provide the potential for malicious authors to deliver scripts to run on a client computer via the Web. Browser authors contain this risk using two restrictions. First, scripts run in a sandbox in which they can only perform Web-related actions, not general-purpose programming tasks like creating files. Second, scripts are constrained by the same origin policy: scripts from one Web site do not have access to information such as usernames, passwords, or cookies sent to another site. Most JavaScript-related security bugs are breaches of either the same origin policy or the sandbox.
Cross-site vulnerabilities
A common JavaScript-related security problem is cross-site scripting, or XSS, a violation of the same origin policy. XSS vulnerabilities occur when an attacker is able to cause a trusted Web site, such as an online banking website, to include a malicious script in the webpage presented to a victim. In that example, the script can then access the banking application with the privileges of the victim, potentially disclosing secret information or transferring money without the victim’s authorization.
XSS vulnerabilities can also occur because of implementation mistakes by browser authors.
XSS is related to, but not the same as, cross-site request forgery or XSRF. In XSRF, one website causes a victim’s browser to generate fraudulent requests to another site, with the victim’s legitimate HTTP cookies attached to the request.
Misunderstanding the client-server boundary
Client-server applications, whether they involve JavaScript or not, must assume that untrusted clients may be under the control of attackers. Thus any secret embedded in JavaScript could be extracted by a determined adversary, and the output of JavaScript operations should not be trusted by the server. Some implications:
* Web site authors cannot perfectly conceal how their JavaScript operates because the code is sent to the client and obfuscated code can be reverse engineered.
* JavaScript form validation only provides convenience for users, not security. If a site verifies that the user agreed to its terms of service, or filters invalid characters out of fields that should only contain numbers, it must do so on the server, not only the client.
* It would be extremely bad practice to embed a password in JavaScript (where it can be extracted by an attacker), then have JavaScript verify a user’s password and pass "password_ok=1" back to the server (since the "password_ok=1" response is easy to forge).
Browser and plugin coding errors
JavaScript provides an interface to a wide range of browser capabilities, some of which may have flaws such as buffer overflows. These flaws can allow attackers to write scripts which would run any code they wish on the user’s system.
These flaws have affected major browsers including Firefox, Internet Explorer, and Safari.
Plugins, such as video players, Macromedia Flash, and the wide range of ActiveX controls enabled by default in Microsoft Internet Explorer, may also have flaws exploitable via JavaScript, and such flaws have been exploited in the past. In Windows Vista, Microsoft has attempted to contain the risks of bugs such as buffer overflows by running the Internet Explorer process with limited privileges.
Sandbox implementation errors
Web browsers are capable of running JavaScript outside of the sandbox, with the privileges necessary to, for example, create or delete files. Of course, such privileges aren’t meant to be granted to code from the Web.
Incorrectly granting privileges to JavaScript from the Web has played a role in vulnerabilities in both Internet Explorer and Firefox. In Windows XP Service Pack 2, Microsoft tightened the rules on what JavaScript would be run with high privileges by Internet Explorer.
Some versions of Microsoft Windows allow JavaScript stored on a computer’s hard drive to run as a general-purpose, non-sandboxed program. This makes JavaScript (like VBScript) a theoretically viable vector for a Trojan horse, although JavaScript Trojan horses are uncommon in practice.
