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...

Here is a list of website CAPTCHA designs which demonstrate all kinds of weird verification methods. By looking at these designs, as a website designer, you should distinguish which design is accessible and which is not.Is this human readable?What characters are in the picture?One moreWe will be crazy if we see theseOMG,What's the answer?IQ Test?Are you a normal person?You know how blind people read?ASCII PictureAre you an adult?3D verification codereCaptchaIt increase a new feature recently. It display the Google Street View address and names . Facebook's face detection : Nice idea, huh?Micro...

TIOBE released the programming language index for July 2013. The highlight of this month is that PHP is coming back. It ranks the fifth and has an increase of 1.54% compared to January. There are no changes in the ranking for the top 4 languages. The reason why PHP is back may be attributed to the new PHP Zend Framework that was released in September 2012, but this reason is not very convincing. PositionJul 2013PositionJul 2012Delta in PositionProgramming LanguageRatingsJul 2013Delta Jul 2012Status11C17.628%-0.70%  A22Java15.906%-0.18%  A33Objective-C10.248%+0.91% ...

In Web 2.0 era, many websites will ask the user to upload their avatar when creating their profile. In HTML, the input control we should use is input="file". This is a file control provided by the browser vendor and it should be ran in a sandbox for security consideration. Browsers don't provide ways to choose file from local and upload to the remote server without the input="file" control. There is one annoying part about the input="file", which is a default button named "Choose File" or "Browser" will always appear when this control is created. Sometimes, to keep consistent and provide ...

Sometimes when we need to use email service provided by WAMP, we need to use some remote mail server such as Gmail. In Gmail, if we want to use the SMTP server to send email and want to use port 465, then the SSL connection should be setup. But by default in WAMP, the ssl is not usable. So to allow use SSL, what we should do is go to system tray and click PHP->PHP Extensions->php_openssl. Then now you can use Gmail to send email easily....

A .htaccess file is a directory-level configuration file supported by several web servers, that allows for decentralized management of web server configuration. What can a .htaccess file do? We summarized some of them here.  Hope it may help you. 1. Timezone settingSometimes when you use date() or mktime() functions in PHP, , it may display some weird information because of the timezone difference. For example, one possible warning is :Warning: date(): It is not safe to rely on the system's timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone...

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...