JS Review

review2013.09.09.js

// We went over:

/*
 * - What's JS used for
 *   - Modifying document structure (the HTML is not the webpage, like the
 *     blueprint is not the building)
 *   - Retrieving data from a server without a page reload
 *   - Widgets and usability
 */

/*
 * - Variables
 *   - Can be defined through assignment
 *   - Can be defined as function arguments
 *   - When not being assigned or used as function arguments, always recalling
 *     the variable value
 */

        var A = 'hello',    // <-- assignment
            B = 3,          // <-- assignment
            C = "goodbye";  // <-- assignment

        alert(C);           // <-- replacing with the value

        var D = B + 2;      // <-- both. make sense?

        function do_something(X, Y) {  // <-- function arguments
          alert(X + Y);                // <-- replacing with the values
        }

/*
 * - Functions
 *   - Are containers for one or more instructions
 *   - Can be "called" to run the contained instructions
 */

        function say_something(words) {
          var sentence = words + '.';
          alert(sentence);
        }

        say_something("hello");
        say_something("this is a test");

// You can copy and paste any of these into the Chrome/Firebug console to try
// them out.

// Also, we didn't go over this, but there are two ways to define functions.
// The following two are exactly the same:

        function my_func(a, b, c) {
          // ...
        }

        var my_func = function(a, b, c) {
          // ...
        }

// The reason is because a function is just a value. Functions are really
// powerful and immportant values. We'll do much more with them soon.