Head First Ajax(1).pdf

Chapter 1. using ajax

Table of Contents

Chapter 1. using ajax. ................................................................................... 1

Section 1.1. Web pages: the old-fashioned approach ..................................................................................................................... 2

Section 1.2. Web pages reinvented ................................................................................................................................................. 3

Section 1.3. So what makes a page "Ajax"?. .................................................................................................................................... 5

Section 1.4. Rob's Rock 'n' Roll Memorabilia ................................................................................................................................. 6

Section 1.5. Ajax and rock 'n' roll in 5 steps .................................................................................................................................. 12

Section 1.6. Step 1: Modify the XHTML ........................................................................................................................................ 14

Section 1.7. Step 2: Initialize the JavaScript ................................................................................................................................. 16

Section 1.8. Step 3: Create a request object. ................................................................................................................................. 20

Section 1.9. Step 4: Get the item's details ..................................................................................................................................... 22

Section 1.10. Let's write the code for requesting an item's details ............................................................................................... 24

Section 1.11. Always make sure you have a request object before working with it ...................................................................... 25

Section 1.12. The request object is just an object ......................................................................................................................... 26

Section 1.13. Hey, server... will you call me back at displayDetails(), please? ............................................................................. 27

Section 1.14. Use send() to send your request .............................................................................................................................. 28

Section 1.15. The server usually returns data to Ajax requests .................................................................................................... 30

Section 1.16. Ajax is server-agnostic .............................................................................................................................................. 31

Section 1.17. Use a callback function to work with data the server returns ................................................................................. 35

Section 1.18. Get the server's response from the request object's responseText property .......................................................... 36

Section 1.19. Goodbye traditional web apps... .............................................................................................................................. 38

Section 1.20. AjaxAcrostic ............................................................................................................................................................. 39

Chapter 1. using ajax

Head First Ajax By Rebecca M. Riordan ISBN: 9780596515782 Publisher: O'Reilly Prepared for Ann Cherkis, Safari ID: maottw@gmail.com

This PDF is exclusively for your use in accordance with the Safari Terms of Service. No part of it may be reproduced or transmitted in any form by any means without the prior

written permission for reprints and excerpts from the publisher. Redistribution or other use that violates the fair use priviledge under U.S. copyright laws (see 17 USC107) or that

otherwise violates the Safari Terms of Service is strictly prohibited.

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using ajax

Web Apps for a New

Generation

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Chapter 1. using ajax

Head First Ajax By Rebecca M. Riordan ISBN: 9780596515782 Publisher: O'Reilly Prepared for Ann Cherkis, Safari ID: maottw@gmail.com

This PDF is exclusively for your use in accordance with the Safari Terms of Service. No part of it may be reproduced or transmitted in any form by any means without the prior

written permission for reprints and excerpts from the publisher. Redistribution or other use that violates the fair use priviledge under U.S. copyright laws (see 17 USC107) or that

otherwise violates the Safari Terms of Service is strictly prohibited.

to use

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old-fashioned web apps

Web pages: the old-fashioned approach

With traditional web pages and applications, every time a user clicks on

something, the browser sends a request to the server, and the server responds

with a whole new page . Even if your user’s web browser is smart about

caching things like images and cascading style sheets, that’s a lot of traffic

going back and forth between their browser and your server... and a lot of

time that the user sits around waiting for full page refreshes.

chan ging... b ut there ’s still a complete page re fresh.

A nd th e serve r

sends back anothe r

who le page ...

2 Chapter 1

Chapter 1. using ajax

Head First Ajax By Rebecca M. Riordan ISBN: 9780596515782 Publisher: O'Reilly Prepared for Ann Cherkis, Safari ID: maottw@gmail.com

This PDF is exclusively for your use in accordance with the Safari Terms of Service. No part of it may be reproduced or transmitted in any form by any means without the prior

written permission for reprints and excerpts from the publisher. Redistribution or other use that violates the fair use priviledge under U.S. copyright laws (see 17 USC107) or that

otherwise violates the Safari Terms of Service is strictly prohibited.

Most of the t ime, only a single line or i mage is

Chapter 1. using ajax Page 3

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using ajax

Web pages reinvented

Using Ajax, your pages and applications only ask the server for what they

really need—just the parts of a page that need to change, and just the parts

that the server has to provide. That means less traffic, smaller updates, and

less time sitting around waiting for page refreshes.

With Ajax, the browser only sends and receives

the parts of a page that need to change.

a spe cial req uest o bject t hat t he

bro wser se nds to the s erver.

request

function

getDetails {

...

}

request

...an d your cod e tells the

b rowser to update only the

parts of the page t hat

have c hanged.

Sometimes the browser doesn’t have to

talk to the server at all.

Th e script can up date th e

image w ithout t he serve r-side

progra m at al l!

function

getDetails {

...

}

Th e scrip t tells the bro wser

how to update the pa ge... all

witho ut a pa ge refr esh.

you are here

Chapter 1. using ajax

Head First Ajax By Rebecca M. Riordan ISBN: 9780596515782 Publisher: O'Reilly Prepared for Ann Cherkis, Safari ID: maottw@gmail.com

This PDF is exclusively for your use in accordance with the Safari Terms of Service. No part of it may be reproduced or transmitted in any form by any means without the prior

written permission for reprints and excerpts from the publisher. Redistribution or other use that violates the fair use priviledge under U.S. copyright laws (see 17 USC107) or that

otherwise violates the Safari Terms of Service is strictly prohibited.

T his ti me, you r page ’s code creat es

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