Head Rush Ajax

180

Chapter 3

using substring in javascript

1Jim

0

1

2

3

Position:

myString.substring(1, 3);

myString

myString.substring(2, myString.length);

myString.substring(0, myString.length);

Ji

im

1Jim

You can use myString.length to get

the length of a string, which will

always be one greater than the

last position in the string.

4

myString.length

This substring will start at position

1, end at position 3, and not

include the character at position 3.

substring() practice

Let’s spend a little time practicing how to use the JavaScript substring()

method, using the string you saw on the last two pages.

JavaScript

PHP script

HTML form

This substring started at position 1

(“J”), and went to position (3 - 1),

which is position 2 (“i”).

Since myString.length will be 1 greater

than the last position, this will always

go to the end of a string.

Position 0 is the rst

character in the string...

...and myString.length will always

return to the end of the string.

This JavaScript would always

return the entire string.

you’re on your way 4

181

asynchronous applications

You should be ready to write the rest of the JavaScript for serveDrink() on

your own now. Below is part of that function’s JavaScript; your job is to ll in

the blanks and get things working.

You’ll need to get the response from the server, then break that response

int ...