Spam comments are annoying and notorious. They are either malicious data from hackers to exploit the loopholes of the site or advertisements posted by robots. These kinds of comments have their own features and patterns, if we are careful enough, we can find ways to block most of them although it's not so easy.To block the comment with malicious executable codes such as JavaScript, we should remember one rule : never trust user input. So wherever there are user inputs, we need to check the validity of the data, we should escape the data inputted by users and remove unnecessary HTML tags from t...

How to make a drop down menu show above of a  flash in webpage?Normally when we embed a flash or swf file into our webpage, it is not one component of our webpage.So sometimes the flash will always show above of the webpage, it will not interact with our HTML page.To solve this problem,we need to use wmode property of object tag.wmode has three properties: window,opaque and transparent.window : the flash will show in its own rectangular window,which will not interact with           our webpage,so it will always show on top of the page.opaque :i...

While reading Hacker News posts about JavaScript, I often come across the misconception that Ruby’s blocks are essentially equivalent to JavaScript’s “first class functions”. Because the ability to pass functions around, especially when you can create them anonymously, is extremely powerful, the fact that both JavaScript and Ruby have a mechanism to do so makes it natural to assume equivalence.In fact, when people talk about why Ruby’s blocks are different from Python‘s functions, they usually talk about anonymity, something that Ruby and JavaScript share...