Book Image

Object-Oriented JavaScript

Book Image

Object-Oriented JavaScript

Overview of this book

Table of Contents (18 chapters)
Object-Oriented JavaScript
Credits
About the Author
About the Reviewers
Preface
Built-in Functions
Regular Expressions
Index

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 this code:

    	>>> var a = getRGB("#00FF00"); 
    	>>> a; 

    "rgb(0, 255, 0)"

  2. What does each of these 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() {
    	  var a = 2;
    	  function n() {
    	    alert(a);
    	  }
    	  n();
    	}
    	f(); 
  4. All these examples alert "Boo!". Can you explain why?

    4.1.

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

    4.2.

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

    4.3.

    	   (
    	    function(){
      	      return alert;
    	    }
    	  )()('Boo!');