Head Rush Ajax

you’re on your way 4

19

next generation applications

If you did the exercise on the previous page, you should have some

code in your boards.html page that looks something like this:

Adding the getBoardsSold() function

<script language=”javascript” type=”text/javascript”>

var request = null;

function createRequest() {

// pre-assembled JavaScript

}

function getBoardsSold() {

createRequest();

}

</script>

Remember, all of the

JavaScript code is

between the <script>

and </script> tags.

Here’s createRequest(), which you

should have added a few pages back.

This is the new

JavaScript function...

...and here’s where the request

object is created, using the

pre-assembled JavaScript.

This is your

request

variable; once

your code calls

createRequest(),

this variable will

point to a new

request object.

So what’s next? You’ve got an object that you can use to request the

board sales from the server, but how do you make that request? First,

you need to tell the object where to send the request—in other words, it

needs to know what program on Katie’s server to send the request to. So

you need to tell it the URL of the script running on the web server.

And where do we get that URL? You can nd it in Katie’s web form:

<form method=”GET” action=”getUpdatedBoardSales.php”>

<input value=”Show Me the Money” type=”submit” />

</form>

But doesn’t the PHP script return a

bunch of HTML right now? I thought

we only ...