In the eighteen years that I've been doing Web development, a lot has changed. We started out creating HTML pages to present static information to our users. We then used classic ASP to get database data and incorporate that into our pages. To use both of these technologies, we had to know a lot about HTML, CSS, and JavaScript. Along came .NET and we started rendering everything on the server-side. We forgot a lot about HTML, CSS, and JavaScript as Web Forms wrapped up a lot of that for us. Web Forms' architecture closely mimicked the way developers created desktop applications. This was great for helping developers move to the Web, but unfortunately hid a lot of the power of the Web, and also tended to be a little slow.

Web developers were demanding that Microsoft get back to the roots of HTTP and HTML, and thus MVC was invented. This technology was very different from Web Forms, but was more closely aligned with how the Web worked. In order to use MVC, you had to get back to your roots of HTML, CSS, JavaScript, and jQuery. Most developers using MVC were still doing a lot of server-side rendering and this meant a lot of post backs, which also still slowed down the user experience.

In my last three articles for CODE Magazine, I introduced you to a pure HTML page that allowed you to list, add, edit, and delete data using the Web API, jQuery, and JavaScript. As you have seen from these articles, this page is very fast, much faster than either Web Forms or MVC's server-side rendering. Unfortunately, the code we've written leaves a little bit to be desired. There are a couple of things we can do to make our code better; namely, JavaScript closures and HTML templating. These two technologies are used extensively in AngularJS, which is a client-side framework that is very popular for Web development today.

In this article, you'll learn to wrap your JavaScript functions and variables into a JavaScript closure. In addition, you'll learn to use mustache.js to create HTML templates and eliminate the coding of HTML in JavaScript. By learning these techniques, you will be that much closer to moving to Angular. When you begin to use Angular you will see a performance gain in your Web pages. This is due to less post-backs and less bytes transferred across the network. There are many other benefits as well, and I will explore these in the next articles.

Introduction to JavaScript Closures

The first step in getting to Angular is to learn about JavaScript closures. Think of a JavaScript closure like a class in an OOP language. Within this closure, you can have private variables, private functions and public functions. To illustrate, let's take the HTML page shown in Figure 1 and the JavaScript to load the HTML table shown in Listing 1 and wrap that up into a closure.

Figure 1      : A list of products
Figure 1 : A list of products

The portion of this page you'll be interacting with is the

element. This element is shown below.

<table id="productTable"
       class="table table-bordered 
              table-condensed table-striped">
      <th>Product Name</th>
      <th>Introduction Date</th>

In Listing 1, there are three main components. There's a variable called products that holds the collection of product data and there's a function called productTableBuild() and a function called productList(). Of these three things, only productList() needs to be public. The other items should be hidden from the global scope of the page. This is where a closure works well. To create a closure, wrap all your variables and functions contained within the