One of the most common tasks a web developer deals with is to add event listeners to the elements of a page. Event listeners are employed to perform one or more actions when a given event occurs on one or more elements.
For example, by using an event listener we could display a dialog when a button is clicked by a user. In this case, the developer is running a single action (showing the dialog) when a click event occurs on one element (the button). Another example is a pagination widget. The latter is made of many links that have to lead the user to a given page when clicked. Here, the developer is performing the same, single action on many elements. The final example I want to mention is to use an event listener with elements that don’t yet exist in the page but will. This happens when injecting elements in the web page after an Ajax request is performed.
In this article, I’ll discuss how you, as a web developer, can optimize the addition of event listeners in all these situations by employing a technique called event delegation.
I was talking with a workmate about the test and he decided to take it despite my warning about its simplicity. We compared the solutions we wrote for two of the six exercises and we found out that they were quite different: his solutions were terse and clever, mine were long and extremely simple in their approach to the problem. These differences have generated an interesting discussion that touched several topics: readability, complexity, performance, and maintainability.
Starting from the analysis of the two exercises we compared and the solutions we wrote, in this article I’ll share my thoughts about the power of simplicity in code.
Who don’t know what jQuery is and how it can help in developing a web project. Based on the latest statistics, jQuery is used on ~60% of the Quantcast Top 100k websites. We use it constantly and sometimes we tend to think it’s almost magic, that jQuery is capable to understand what we want to achieve and optimize all for us. There is no need to say this is wrong. You need to be aware of what jQuery does and does not for you and optimize as much as you can to improve your website’s performance.
In this article, extracted from my book Instant jQuery Selectors, you’ll learn some useful tips and tricks to improve the performance of your website by simply selecting elements in the right way.