ITM 352 - © Port, Kazman1 ITM 352 HTML Forms, Basic Form Processing

ITM 352 - © Port, Kazman 1

ITM 352

HTML Forms, Basic Form Processing


Some Inspiration!

Perseverance: never giving upIndomitable Spirit: never wanting to give upFormula for success

Perseverance + Indomitable Spirit = Success

Indomitable Spirit “Get to your limit and see what’s on the other side” - Yoga "Try not. Do, or do not. There is no try." - Yoda “Suffering is optional” – Yoghurt “If you’re brain is hurting it just means you’re learning” – P2


What We Will Cover Today

Today we will explore HTML forms in some detail: Details on <FORM> Input types Compound types Some tips for HTML form elements


Form Parts

<form action = 'xxx' method = 'yyy'>

<form stuff goes here>

</form>

action is the file you want to go to (could be html or php)

method should be either POST or GET


Action An action should be a URI (e.g. a file name in the current

folder) or a full web address, e.g. http://www.somewebserver.com/myfile.php)

Example:<form action = 'invoice.php'>

…</form>

This will take the user to the invoice.php page in the current directory when the user presses the submit button.

Note: You should always use quotes around the URI in case it has special characters or spaces.


Method

The method can be either 'POST' or 'GET'. $_GET and $_POST are arrays built into PHP

which make form processing a lot easier. Form variables are stored as keys (elements) of

these arrays, indexed by their name To see what is in the array just do a var_dump() e.g. var_dump($_GET);

TIP: put var_dump()at the top of form processing files so you can see what is sent from the form


Submit Button

Usually you need to have a submit button to invoke a form's action, e.g.:

<input type = 'SUBMIT'

name = 'the name you want to appear in the POST/GET array'

value = 'the label in the button '

>


Example: Login

<form action ='invoice.php' method = 'POST'>

<input type = 'SUBMIT' name = 'submit_button' value = 'Login'>

</form>

Do Lab #1


Input types (single value)

A generic input type looks like this:

<input type = '<type>'

name = '<the name in the POST/GET array>'

value = '<the value you want to set it to>'

>


The Basic Input Types

TextPasswordHiddenRadio CheckboxSubmit


Login <?php

print "logged in " . $_POST['username'];

?>

<form action = 'process_login.php' method = 'post'>

<input type = 'text' name = 'username'>

<input type = 'password' name = 'password'>

<input type = 'submit' name = 'submit_button' value = 'login'>

</form>

Do Lab #2


Self-Processing Form

Sometimes you want to stay on the same page when processing your forms

<form action = '<?= $_SERVER["PHP_SELF"]?>' method = 'post'>

</form>

is the same as:

<form action = '<?php $_SERVER["PHP_SELF"] ?>'method = 'post'>

</form>

<?= is short for echo when embedding PHP in HTML

You can use $PHP_SELF or $_SERVER['PHP_SELF']


Login if( array_key_exists('submit_button', $_POST) ) { print "logged in " . $_POST['username'];}else {?><form action = '<?php $_SERVER['PHP_SELF'] ?>' method =

'post'><input type = 'text' name = 'username'><input type = 'password' name = 'password'><input type = 'submit' name = 'submit_button' value =

'login'></form>

<?php } ?>Do Lab #3


GET method

<form method = 'get'> … </form>

GET will show the information being passed between pages as part of the URL. Good tool for error checking However, it is not secure because users can see

the full contents of the request. Pages can be cached.


POST method

<form method = 'post'> … </form>

POST will hide information being passed between pages in the address bar. HINT: use GET for error checking; change to

POST when submitting your work More secure than GET Pages won't be cached.

Do Lab #4


Compound Types

Select Text area List box

Compound types enable multiple inputs and/or outputs

Unlike input types, compound types always use a begin and end tag

<select name='a_select_box'> … </select>


Login if( array_key_exists('submit_button', $_POST) ) { print "logged in " . $_POST['username'];}else {?><form action = '<?php $_SERVER['PHP_SELF'] ?>'

method = 'post'><select name='username'><option>Moe</option><option>Larry</option><option>Curly</option></select><input type = 'password' name = 'password'><input type = 'submit' name = 'submit_button'

value = 'login'></form><?php } ?>


Select Boxes

Select boxes provide a drop down set of options for the user to choose from. Value is whatever the user chooses when the submit

button is pressed If no value parameter is set, the value defaults to the

label <SELECT name="a_select_box">

<OPTION value="value_of_thing1">thing1</OPTION><OPTION value="value_of_thing2">thing2</OPTION><OPTION value="value_of_thing3">thing3</OPTION></SELECT>


Text Area

Text Area provide a region of size row X cols to display and input text. Value is whatever is in the area when the

submit button is pressed

<TEXTAREA name="a_test_area" rows="20" cols="40">

This is some text in the text area.

</TEXTAREA>


Tips and Hints

Use single ' ' on the inside, " " around the outside or vice versa

Take advantage of PHP by using for/while/foreach to generate multiple form elements and compound types

Quotes must be used around anything with spaces

Do Extra Credit (optional)

Documents

ITM 352 - © Port, Kazman1 ITM 352 HTML Forms, Basic Form Processing