In general, you need two directories: "public_html" and a subdirectory of "public_html" called "php". The public_html and the php directory should both be world readable and executable. You may also need to change the permissions for your top level directory. The following commands create the directories and set the permissions in a typical Unix environment. On Windows in a WAMP-like environment, the permissions are most likely automatically set at the time of installation.
cd; chmod 711 .;
mkdir public_html; chmod 755 public_html;
cd public_html; mkdir php; chmod 755 php;
All html files should be in the public_html directory, all
php files in the php directory. The php files should have an extension ".php".
The URL for the html files is
http://someserver/~username/filename.html. The URL for PHP files is
<head><title>Hello World</title></head> <body>
as a file in your public_html directory on the webserver. (On Unix the file permissions of this file should be -rw-r--r--. Type ls -l to check the file permissions. You can set the permissions with chmod 644 filename.) Now, look at the file through your browser.
2) Now save the same html file as above in your php directory under the name greetings.php. (On Unix the file permissions should be -rwxr-xr-x. You can set the file permissions with chmod 755 greetings.php.) Look at the file through your browser.
|user requests |
| server finds HTML file |
and sends page back
|user requests |
| server finds the HTML form |
and sends it back to user
|user fills out form|
| PHP application executes|
program and sends results
back to user
<input type="radio" name="drink" value="tea" checked >
<input type="radio" name="drink" value="coffee" > Coffee <br>
<input type="radio" name="drink" value="hot chocolate" > Hot Chocolate <p>
<input type="submit" value="Place order">
Note: in older or less secure installations of PHP, it is possible to use a variable $drink instead of $_REQUEST['drink']. This is a very insecure practise because in that way your script can't tell whether $drink is an internal variable of the script or whether it comes from a form. See the PHP manual for more information about register globals.
5) Add a checkbox to the form (such as "Do you want milk? Yes/No") and a text area where customers can type in what kind of cake they would like to order. Change your PHP script so that it includes these in its reply, such as "you requested tea with milk", "sorry we are out of chocolate cake". The checkbox and text area must have distinct names in the form.
Select a picture:
All four URLs link to the same PHP file ("greeting.php") which uses a parameter ("image") to distinguish between the four images. This PHP file should produce a form with textboxes for the recipient's email address, the recipient's name and the message.
Upon submitting this form a second PHP file is invoked, which sends an email to the recipient. Because sending email from a form can be a security risk, you should not attempt this before security has been discussed in the lecture.
7) The greeting card example shows that parameters can be added to a URL (for example "greeting?image=3"). Try what happens if you enter parameter values other than 1, 2, 3 or 4. Add an if statement to your PHP script that prints "not an acceptable selection" if the image number is not 1, 2, 3 or 4.