Given the background of Lars Bak, the Google engineer whose V8 JavaScript interpreter upended Firefox's claim on speed, it was reasonable to suspect Google's new Web development language might look a lot like Smalltalk. But that might have taken the Web in a strange and different direction. Today, on the day of a Web developers' conference in Denmark, Google and members of the Chromium open source development team raised the curtain on Dart, the company's bid for a new and somewhat more structured approach to Web programming.Making Dart work will require a new virtual machine, which puts ...

The design of JavaScript is not so sophisticated. It's very easy for us to make mistakes if we are not very careful when using JavaScript. For example, to check the existence of JavaScript object.Now we want to check whether a global object myObj exists or not, if it doesn't exist, we declare it. The pseudo code for this is :if(myObj not exist){ declare myObj;}You may think it's very easy to write the code. In fact, it is much more difficult than we may think. Juriy Zaytsev says there are more than 50 ways to check whether a JavaScript object exist or not. Only if you are very clear about the ...

To ensure security and reduce spamming, modern browsers have implemented very strict rules on when a new window can be opened in a web page. Currently browsers restrict that any new web page to be opened in a new window must be initiated with an user action. The action is usually an user click event. Otherwise, a popup blocker would show on the browser address bar which indicates that something is blocked.To workaround this issue, normally you should implement the window open logic in a click event handler. An example code block would look like:jQuery("#some_element").click(function(){ var win...

Following my article A String is not an Error, I want to bring attention to an issue that similarly applies to JavaScript in general, but has special relevance in the Node.JS environment.The problem boils down to the usage of {} as a data-structure where the keys are supplied by untrusted user input, and the mechanisms that are normally used to assert whether a key exists.Consider the example of a simple blog created with Express. We decide to store blog posts in memory in a {}, indexed by the blog post slug. For example, this blog post would be posts['an-object-is-not-a-hash'].We start writin...

What is pjax?Now many websites such as Facebook, Twitter support one browsing style which is when you click one link on their sites, the page will not be redirected, instead only the page contents are updated and URL on address bar is changed. This kind of user experience is much better compared to load the whole page with a blink.There is one important component in the above browsing experience, these websites' AJAX refresh support browser history, when refreshing the page, the address on the address bar will also get updated, and when we click back button we can go back to the previous page....

In some cases, one would want to convert a HTML string to the DOM elements so that JavaScript can handle them easily. This is frequently used when one get some data from third party APIs where the data is in HTML format.In JavaScript, there are a couple of ways one can use to convert HTML to DOM elements.DOMParserdocument.createElementDOMParserDOMParser can parse XML or HTML source stored in a string into a DOM Document. After the conversion, the normal JavaScript call of handling DOM elements can be used, like getting element by id or using selectors.For example, assuming there...

In early 2006, Alex Russell posted about a neat hack that the Google Talk team in Gmail use to support Comet in Internet Explorer, a trick which works as far back as IE 5.01. What great news! A reliable way to stream Comet messages to Microsoft’s browsers. If only it were that easy.I have not been alone in the following findings: after connecting the htmlfile ActiveX object as a streaming Comet transport to my Comet server, everything works perfectly for a few messages, but then abruptly fails. The connection is closed by the browser with the server-side error “Connection reset by...

D3.js is a very popular graph library to help developers draw various kind of charts using JavaScript in a webpage. It utilizes the SVG format supported by all major modern browsers and can help developers get rid of the old age of Flash or server side graph drawing libraries.In this post, we will introduce some simple examples of drawing bar chart with labels using D3.js. First, let's see what will be the final look of the graph drawn.Below is the complete source code for this example.let data = { "FACEBOOK": 30, "GITHUB" : 44, "GOOGLE" : 64, "TWITTER" : 17, "WEIBO" : ...