University of Washington CSE 154
Section 6: JSON and Basic PHP
Except where otherwise noted, the contents of this document are
Copyright © Marty Stepp, Jessica Miller, and Victoria Kirst.
All rights reserved.
Any redistribution, reproduction, transmission, or storage of part
or all of the contents in any form is prohibited without the author's
expressed written permission.
IMPORTANT NOTES:
-
Factoring Your AJAX:
- PLEASE comment complex blocks of code.
Exercise : Address Book, Client-Side (by Alex Miller)
Write the JS code to connect to a server-side JSON address book called
.
Start from this .
()
()
-
A GET request to
addressbook.php with no parameters outputs an array of names:
{"names": ["Suzie", "Billy", ...]}
-
A GET request with a
name parameter outputs that person's address:
{"name": "Billy", "address": "123 4th St."}
-
A POST request with a
name and address parameter saves that person in the address book.
Recall: Creating an Ajax POST request
var params = new FormData();
params.append("name", value);
params.append("name", value);
var ajax = new XMLHttpRequest();
ajax.onload = functionName;
ajax.open("POST", "url", true);
ajax.send(params);
Exercise : Kitties (by Alex Miller)
Given 5 image files (kittie1.jpg, kittie2.jpg, etc.), write a PHP page that displays all 5 images as seen
(view source on output to get starter code!).
Exercise solution
<!DOCTYPE html>
<html>
<head>
<title>kitties</title>
</head>
<body>
<div>
<?php for ($i = 1; $i <= 5; $i++) { ?>
<img src="kittie<?= $i ?>.jpg" />
<?php } ?>
</div>
</body>
</html>
Exercise : Buggy PHP
The following PHP pages each contain one or more bugs.
The bugs could be syntax errors or incorrect logic.
Look at each page, find the bug(s), and correct the errors.
-
() - variables, strings, if/else
-
() - variables, if/else, comments
-
() - variables, for loops, string concatenation
-
() - arrays, foreach
-
() - arrays, foreach
Exercise debugging tips
-
Look at the error messages, if any, and examine those lines in your PHP source file.
(You may need to enable line numbers in your editor.)
-
Check for mismatched brackets. Many editors support bracket matching.
-
PHP's error messages are not very friendly, often mentioning internal terms like
T_VARIABLE and $end.
If you don't understand an error, try Googling for the error message.
-
If there is no error message, try printing the value of variables at various points in the code.
Use
print for simple variables and print_r or var_dump for arrays and objects.
Exercise : Fibonacci (by Rishi Goutam)
Modify the following to print the first 20 Fibonacci numbers in an ordered list using PHP.
Recall that in the Fibonacci sequence, each number is the sum of the two previous numbers, with the first and second numbers being 0 and 1.
<!DOCTYPE html>
<html>
<head>
<title>Fibonacci Sequence</title>
</head>
<body>
<h1>The first twenty Fibonacci numbers:</h1>
<!-- (your code here!) -->
</body>
</html>
Exercise solution
...
<h1>The first twenty Fibonacci numbers:</h1>
<?php
$first = 0;
$second = 1;
for ($i = 0; $i < 20; $i++) {
?>
<li><?= $first ?></li>
<?php
$temp = $second;
$second += $first;
$first = $temp;
}
?>
