Sams Teach Yourself JavaScript in 24 Hours

By Michael Moncur

• Table of Contents
  • Copyright
  • About the Author
  • Acknowledgments
  • We Want to Hear from You!
  • Reader Services
  • Introduction
  • Part I: Getting Started
  • Hour 1. Understanding JavaScript
  • Hour 2. Creating a Simple Script
  • Hour 3. How JavaScript Programs Work
  • Part II: Learning JavaScript Basics
  • Hour 4. Using Functions and Variables
  • Hour 5. Using Strings and Arrays
  • Hour 6. Testing and Comparing Values
  • Hour 7. Repeating Yourself: Using Loops
  • Hour 8. Using Math and Date Functions
  • Part III: The Document Object Model (DOM)
  • Hour 9. Working with the Document Object Model
    • Understanding the Document Object Model
    • Using window Objects
    • Working with Web Documents
    • Accessing Browser History
    • Working with the location Object
    • Reading Information about the Browser
    • Workshop: Creating Back and Forward Buttons
    • Summary
    • Q&A
    • Quiz
    • Exercises
  • Hour 10. Responding to Events
  • Hour 11. Using Windows and Frames
  • Hour 12. Getting Data with Forms
  • Hour 13. Using Graphics and Animation
  • Part IV: Moving on to Advanced JavaScript Features
  • Hour 14. Creating Cross-Browser Scripts
  • Hour 15. Creating Custom Objects
  • Hour 16. Working with Sounds and Plug-Ins
  • Hour 17. Debugging JavaScript Applications
  • Part V: Working with Dynamic HTML (DHTML)
  • Hour 18. Working with Style Sheets
  • Hour 19. Using Dynamic HTML (DHTML)
  • Hour 20. Using Advanced DOM Features
  • Part VI: Putting It All Together
  • Hour 21. Improving a Web Page with JavaScript
  • Hour 22. Creating a JavaScript Game
  • Hour 23. Creating DHTML Applications
  • Hour 24. JavaScript Tips and Tricks
  • Part VII: Appendices
  • Appendix A. Other JavaScript Resources
  • Appendix B. Tools for JavaScript Developers
  • Appendix C. Glossary
  • Appendix D. JavaScript Quick Reference
  • Appendix E. DOM Quick Reference

Working with the location Object

A third child of the window object is the location object. This object stores information about the current URL stored in the window. For example, the following statement loads a URL into the current window:

window.location.href="http://www.starlingtech.com";

The href property used in this statement contains the entire URL of the window's current location. You can also access portions of the URL with various properties of the location object. To explain these properties, consider the following URL:

http://www.jsworkshop.com:80/test.cgi?lines=1#anchor

The following properties represent parts of the URL:

• location.protocol is the protocol part of the URL (http: in the example).
• location.hostname is the host name of the URL (www.jsworkshop.com in the example).
• location.port is the port number of the URL (80 in the example).
• location.pathname is the filename part of the URL (test.cgi in the example).
• location.search is the query portion of the URL, if any (lines=1 in the example). Queries are used mostly by CGI scripts.
• location.hash is the anchor name used in the URL, if any (#anchor in the example).

The link object, introduced earlier this hour, also includes this list of properties for accessing portions of the URL.

The location object has two methods:

• location.reload() reloads the current document. This is the same as the Reload button on the browser's toolbar. If you optionally include the true parameter, it will ignore the browser's cache and force a reload whether the document has changed or not.
• location.replace()replaces the current location with a new one. This is similar to setting the location object's properties yourself. The difference is that the replace method does not affect the browser's history. In other words, the Back button can't be used to go to the previous location. This is useful for splash screens or temporary pages that it would be useless to return to.

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