Object-Oriented JavaScript - Third Edition

Exercises

1. Write a function that converts a hexadecimal color, for example blue (#0000FF), into its RGB representation, rgb(0, 0, 255). Name your function getRGB() and test it with the following code (hint: treat the string as an array of characters):

           > var a = getRGB("#00FF00"); 
           > a; 
           "rgb(0, 255, 0)" 
   

2. What do each of these following lines print in the console?

           > parseInt(1e1); 
           > parseInt('1e1'); 
           > parseFloat('1e1'); 
           > isFinite(0/10); 
           > isFinite(20/0); 
           > isNaN(parseInt(NaN)); 
   

3. What does this following code alert?

           var a = 1; 
    
           function f() { 
            function n() { 
               alert(a); 
             } 
             var a = 2; 
             n(); 
           } 
    
           f(); 
   

4. All these following examples alert "Boo!". Can you explain why?
   • Example 1:

             var f = alert; 
             eval('f("Boo!")'); 
     

   • Example 2:

      var e; var f = alert; eval('e=f')('Boo!'); ...