My first blog post on iphone subject reveal a big memory bug when using UIWebView component. This is the (only one) component to display some HTML content in an iphone interface. UIWebView object has a lot of differents issues and I’m going to highlight the biggest of them. Actually, all XMLHttpRequests used in javascript code are fully leaking!!! I mean when you do a request that retrieve 100ko of data, your memory used grow up for 100ko! This bug is not always active, but almost always. In fact the trigger to enable it is to simply open one link in your UIWebView. For example, clickin...

The world of software is made slightly crazy because of the huge flexibility within any computer language. Once you have absorbed the idea of a compiler written in the language it compiles what else is there left to gawp at? But... a Java Virtual Machine JVM written in JavaScript seems like another level of insanity.In fact it is a quite reasonable idea which is only made mad by the usual positions that Java, the top dog, and JavaScript the underling, usually occupy. Java is compiled not to machine code but to a special byte code which is then run on a virtual machine which is usually implemen...

In IE7, the JavaScript setAttribute("style","attributes") doesn't work, but it works in IE 8 and other web  browsers. To solve the STYLE problem in IE 7 we can use a workaround method.we can use element.style.cssText = 'color:#FF0000;';in IE 7 instead ofelement.setAttribute('style','color:#FF0000;');...

In Firefox 8, we’ve added support for insertAdjacentHTML(). It’s an ancient feature of Internet Explorer that has recently been formalized in HTML5 and then spun out into the DOM Parsing specification. The bad news is that Firefox is the last major browser to implement this feature. The good news is that since other major browsers implement it already, you can start using it unconditionally as soon as the Firefox 8 update has been rolled out to users.Basic UsageinsertAdjacentHTML(position, markup) is a method on HTMLElementDOM nodes. It takes tw...

This post is about JavaScript performance but I would like to start it by telling a story that might seem unrelated to JS. Please bear with me if you don’t like C.A story of a C programmer writing JavaScriptMr. C. is a C programmer as you can probably guess from his name. Today he was asked by his boss to write a very simple function: given an array of numbered 2d points calculate vector sum of all even numbered points... He opens his favorite text editor and quickly types something like (I’ll be intentionally skipping some #include boilerplate):typedef s...

Well, that was a veritable shitstorm (sorry for the language).  Long story short, MelonCard was featured today on TechCrunch (along with other500Startups companies, also on VentureBeat, Forbes, …) and everything broke all at once.  Every. little. thing.  We had rolled out a huge change to MelonCard over the last few days to make our site a seamless “everything just updates” look-good / feel-good product using NodeJS long-polling with a slick KnockoutJS dynamic jQuery Templates front end.  We did our du...

Client-side analytics is broken. The numbers produced by it are trivially spoofable by competitors and nefarious characters. Most websites use client-side analytics of one type or another and the only way to get numbers you can trust is to compare numbers from multiple providers and to take an average of the closest two.This post highlights the problem and proposes a partial solution that substantially mitigates the issues with minimal effort. Our proposed solution is simply to include a digital signature in each message sent to the analytics provider. Apart from the server-side generatio...

What do you need to know if you are interviewing for a job that involves Javascript development? What kind of expectations do employers have of candidates now that the state of client side development has been changed with the rise of asynchronous JavaScript and the often slick, supporting interfaces? These were questions I was asking myself after a friend pointed me to an interesting job posting over at Meebo that included some JavaScript puzzlers on logical operators, DOM oddities and… well that’s all I should say so as not to drop any hints. At any rate I thought...