Chapter 7, The Browser Environment

Lets practice the following exercise:

Exercises

1. The title clock program is as follows:

           setInterval(function () { 
             document.title = new Date().toTimeString(); 
           }, 1000); 
   

2. To animate resizing of a 200 x 200 pop up to 400 x 400, use the following code:

           var w = window.open( 
               'http://phpied.com', 'my', 
                'width = 200, height = 200'); 
    
           var i = setInterval((function () { 
             var size = 200; 
             return function () { 
               size += 5; 
               w.resizeTo(size, size); 
               if (size === 400) { 
                 clearInterval(i); 
               } 
             }; 
           }()), 100); 
   

   Every 100 ms (1/10th of a second) the pop-up size increases by five pixels. You keep a reference to the interval i so you can clear it once done. The variable size tracks the pop-up size (and why not keep it private inside a closure).

3. The earthquake program is as follows...