Form Processing With PHP

8/8/2019 Form Processing With PHP

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Form Processing with PHP: Part 1

Fri, 06/30/2000 - 04:00 onaje


Form Processing

Forms are usually used to gather information from visitors to your website. Once you've

gathered the information, it can be used in several ways. It can be sent via email for someone to

read, saved to database, or used to find data in the database that matches a specific criteria.

For example:

If you had a guest book that automatically save guests' comments into a database, you would

use a form on the guest book page to the comments into the database. To search your database

for what a specific guest said, you would can use a search form to pull individual guest

comments out of the database.

There are two parts to a form: the form fields that a visitor enters information into and the script

that process the information.

The typical sequence:

Display an empty form to the user

User fills out the form

User submits the form for processing when s/he is done filling out the form

Verify that the data entered into the form is valid and let the user know about an error if it occurs

Use the gathered data to perform an action

Form construction:

The form tag sets up the form properties.


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ENCTYPE: Encryption type for the data. The default MIME-type for form submission is

application/x-www-form-urlencoded. This MIME-type will take your text and will remove any

spaces and punctuation, replacing them with special character codes. The text/plain MIME-type

is often used with mailto form method to send data as plain text. The multipart/form-data MIME

type splits the form data into a number of separate parts, one for each form element, and then

sends the parts, each encoded in their own different way. This is used when uploading files with

a form.

METHOD: How the data gets treated (GET or POST), MAILTO

The GET method - the form data is combined into a string, and this string is added on to the end

of a url - for example: http://www.examplesite.com/form.php?first=firstname&last=lastname.

GET limits the amount of data that you can collect and submit to a script at one time.

The POST method groups the data together and sends it to the program by HTTP (HyperText

Transfer Protocol), you don't see what data is being sent. POST is recommended for PHP

because you can send more data

MAILTO: the mailto: method sends form data to a specific email address

ACTION: the location of script that will process the form.>

Form Elements:

Within a form tag, there are form elements. Each form element should have a name and a

value.

The name of the form element identifies the information being sent to a script. The value of the

form element is the actual data.

Input field Tags: Usually contains a short line of text.

< input type="text" name="a name" value=" a value A" size="#" maxlength="#" checked >

Input Attributes:

TYPE: Determines what kind of input field is shown in the form.

TEXT

PASSWORD

CHECKBOX
http://www.examplesite.com/form.php?first=firstname&last=lastnamehttp://www.examplesite.com/form.php?first=firstname&last=lastname


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RADIO

HIDDEN

NAME: Sets the name of the form element, whose value will be assigned as the value of a

variable in the script. If the visitor does not fill out this field, and you did not give it a default

value, the value will be sent to the script as undefined.

VALUE: Sets the value of the form element. This can be pre-set to a defalut value or left blank

for the user to enter information* OPTIONAL *.

SIZE: Sets the size of the input ( Text and Password ) * OPTIONAL *.

MAXLENGTH: Sets the maximum number of characters typed in the input box ( Text and

Password ) * OPTIONAL *.

CHECKED: In Radio or Checkboxes, this pre-selectes an element before the user chooses it.

The different types of input type styles:

Text field: A text field allows numbers and characters to be entered.

first

Password: Same as a text field, however *'s appear instead of what the user types into the field.

< input type="password" name="second" value="" size="15" maxlength="15" >

Checkboxes: A group of boxes that can be selected. Usually denoted with squares, and a values

MUST be declared. ( Multiple boxes may be checked )

< input type="checkbox" name="third" value="pen">Pen

Paper


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Pen

Paper

Radio: The same as a checkbox, however if the 'names' are the same you can only select one of

the radio buttons. (Again a value MUST be declared)

< input type="radio" name="fourth" value="pencil" > Pencil

< input type="radio" name="fourth" value="crayon" checked > Crayon

Pencil

Crayon

Hidden: The hidden input filed, works exactly like the text field, however the user can't enter

anything into this box and it is not visible in a form, if you look at the source code of a page you

will be able to tell if a form has a hidden input field. It's best used to pass values that you don't

want the user to change. (A value MUST be declared)

< input type="hidden" name="fifth" value="Invisible Ink">You can't see me Invisible Ink

Select List boxes:

Select: The select list box lets you choose from a list of predefined choices

< select name="sixth" >

< option value="blue" > Blue ink

< option value="black" selected > Black ink

< option value="reds" > Red ink

< /select >

SELECTED pre-selects a choice.

SIZE Sets the size of the select list box * OPTIONAL *.


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Multiple Select: The multiple-select box lets you choose more than one choice from a list of

predefined choices

Hold down the 'Ctrl' key while clicking the mouse to select more than one choice.

Blue ink

Black ink

Red ink

Purple ink

Textarea: Allows a user to type a large amount of text into a text field. The 'wrap' attribute

determines how text in the textarea will behave.

Wrap attribute:

Physical: Press the 'enter' key for a new line

Virtual: New line is created when the sentece typed reaches the end of the column width

Hard: New line created by pressing the 'enter' key or when the end of the column width is

reached.

Size attributes:

Cols: Sets how many columns the textarea will be

Rows: Sets how many rows the textare will be

Reset / Submit: Creates the buttons for submitting and reseting the form.

Submit!


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Reset!

Forms can be implemented using either a single or multiple page design. The single page

technique utilizes a self-referring script to display and process the form. Multi-page forms take

the user through a series of pages to enter, confirm and submit the data.

The other important area to consider when thinking about form design is the reporting

mechanism for invalid data. Some people like to display the form with the input highlighting any

errors. This makes it simple for the user to find and fix problems in the data. Others prefer to

keep the page and application design as simple as possible by reporting errors on a separate

page. The user then needs to either go back to the original form using the back button on their

browser or they may be presented with a link to a page which will contain their entered data.

Putting it together:

When a form is submitted, all HTML variables are passed to a PHP script and assigned their

respective variable names. In our example, the input text field is named "UserName" so when

the form is submitted $UserName will hold the value. The variable $submit, that corresponds to

the input name="submit", will hold the value "click". It is only set if we click the submit button

and not when we directly access input.php with our browser.

PHP code for 'input.php'. It creates a form to allow users to enter their name.

PHP Code:


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";

?>

Remember to escape quotation marks, by putting a slash before them, if you're using 'echo' or

'print' to output HTML.

This section shows what will be seen, when the file is viewed in a HTML browser.

Web Browser Result:

Principio del formulario

EnterYourName

Final del formulario

Retrieving The Input When Submit is Clicked

Now we will add a simple condition to the beginning of our previous example. If the user clicked

the submit button then print out the name that was entered in the text field; otherwise, we

display the HTML form again.

Because the action in the form points to input.php our script will be called again when the user

clicks submit.

PHP Code:


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echo "

Enter Your Name

";

}

?>

See it in action. Get complete code.
http://onaje.com/code/input.phphttp://onaje.com/code/input.phpshttp://onaje.com/code/input.phpshttp://onaje.com/code/input.phphttp://onaje.com/code/input.phps


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Using forms with PHP: part 2

Thu, 08/24/2000 - 04:00 onaje

Form Processing with PHP Part 2

Radio buttons, checkboxes, select lists

Radio Buttons:

data

VALUE: Sets the value of the form element.

RADIOSET links a group of radio buttons together, only one radio per set can be checked.

RADIOSET is alsothe name of the variable that will contain the value submitted by the form.

CHECKED is an optional attribute that makes a radio button active by default.

If the value is not set, "on" is the default value submitted. You can't tell which button in the set

was chosen.

How many days in a week ?:

5

6

7

What is the first day of the week?:

monday

sunday

saturday

PHP Code:


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Note: To pass multiple values, as in a "Checkbox or "Multiple Select List Box", put [] after the

variable name. This tells PHP to treat the form field as an array and each assignment of a value

to formfield[] adds an item to the array. The first item becomes $var[0], the next $var[1], etc.

Then on the receiving page, you simply do a count() on the list of variables that were selected.

Also see the PHP FAQ
http://onaje.com/code/radio.phphttp://onaje.com/code/radio.phpshttp://onaje.com/code/radio.phpshttp://onaje.com/code/radio.phphttp://onaje.com/code/radio.phps


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Checkboxes:

Checkboxes are linked by their name attribute, similar to radio buttons. Unlike radio buttons

checkboxes can accept more than one answer per set.


BOXSET links a group of checkboxes together, more than one checkbox per set can be checked.

BOXSET is alsothe name of the variable that will contain the values submitted by the form.

CHECKED is an optional attribute that makes checkboxes active by default.

If the value is not set, "on" is the default value submitted. You can't tell which checkbox in the

set was choosen.


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Select List Boxes:

data


SIZE is the number of options from the select list that will be visible to the user

MULTIPLE is an optional attribute that allows a user to select more than one option from the

select list using the Ctrl or Command key.

SELECTED is an optional attribute that makes an option in the select list active by default.

If the size is larger than the number of options in the list, clicking in the empty space will

deselect all values.

1. Single Select:

How old are you?

How many years older is your brother/sister?

0

1

3

4

5

PHP Code:


Multiple Select:
http://onaje.com/code/single.phphttp://onaje.com/code/single.phpshttp://onaje.com/code/single.phpshttp://onaje.com/code/single.phphttp://onaje.com/code/single.phps


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None

white

black

blue

brown

green

yellow

red

orange

purple

PHP Code:

http://onaje.com/code/multi.phphttp://onaje.com/code/multi.phpshttp://onaje.com/code/multi.phpshttp://onaje.com/code/multi.phphttp://onaje.com/code/multi.phps


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Using forms with PHP: part 3

Thu, 09/28/2000 - 04:00 onaje


How to populate form fields with previously submitted values.

When you see the scripts in action, take a look at the source code, especially what the values of

the form fields are set to before and after the scripts execute.

Input field:

To automatically have the value of an input field filled out, use the echo/print function to place

the value submitted into the value attribute of the field.

PHP Code:

What is your first name?

//Check to see if a value was submited then write it to the value

attribute of the input field

....


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}

?>


Select List Boxes:

To automatically have a select list display the option value that you selected when you

submitted the form, check to see if the variable is not empty and isn't the default value. If

there's a value for the variable, use the echo/print function to output an option with the

previously submitted value.

PHP Code:

A leap year occurs every

//Check to see if, the value submited is not - select number -

//then set the value of the option to contains the preselected value

1
http://onaje.com/code/populate1.phphttp://onaje.com/code/populate1.phpshttp://onaje.com/code/populate1.phpshttp://onaje.com/code/populate1.phpshttp://onaje.com/code/populate1.phphttp://onaje.com/code/populate1.phps


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2

..... years.

....

See it in action. Get complete code

Check Boxes:

Place checkbox values into array using implode function" $cols = implode($colors, ",");

When you want to see what check boxes were checked, you use the explode function to get the

values from the array: $colarray=explode(",",$cols);

In the case where you are placing values into a database, you would insert the value of $cols

into a table column, then retrieve the value of the table column and assign it to a value, i.e.

$tablecolumn, then use the explode function - $cols=explode(",",$tablecolumn);

PHP Code:
http://onaje.com/code/populate2.phphttp://onaje.com/code/populate2.phpshttp://onaje.com/code/populate2.phpshttp://onaje.com/code/populate2.phphttp://onaje.com/code/populate2.phps


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What color(s) do you like?

//Check to see if a boxset value is the array, if it is, make the

checkbox active

>Yellow

....

....


Radio Buttons:

Are basically the same as checkboxes, but only one value can be checked if you give the same

name to set of radio buttons. You must give the buttons different names if you want to select

more than one.

PHP Code:


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//get the values of the radioset from an array

$vals=explode(",",$dinero);

?>

How much money would you like to earn per week?

//Check to see if a radioset value is the array, if it is, make the radio

button active

>100

....

....


Textareas:

make sure there is no whitespace in your file because when echoing back your info in the textare

it may not appear correctly.

PHP Code:


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What is your favorite food to eat?

//Check to see if a value was submited then write it between the textarea

tags

}else{

?>

....



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Checkbox In Form

I've created in a form:


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Form Processing with PHP: part 4

Thu, 01/18/2001 - 05:00 onaje

Form Validation

Validating a form

You can perform form validation before a form is submitted via JavaScript or after the form is

submitted via PHP.

I've actually already demonstrated simple validation using PHP in Form Processing with PHP:

Part 1, with the input.php script. After the form is submitted, the script checks to see whether a

variable does or does not exist.

PHP Code:


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You can also use regular expressions with the ereg() and eregi() functions to validate the values

submitted by a form. Regular expressions examine a string and search for patterns and

variations to determine whether they match the search criteria you set.

An example:

This regular expression tests true if the user has entered only characters, from a to z, in

lowercase or uppercase, and numbers from zero to nine. Also, checks whether the string is four

to twelve characters in length.

The ^ indicates the beginning of a string and the $ the end of the string.

if (!ereg("^[A-Za-z0-9]{4,12}$",$Username)): echo "Your username must be at least 4

character, but not more than 12 characters.";

PHPBuilder.com has a good tutorial demonstrationg how to use regular expressions called

Learning to Use Regular Expressions by Example.

You could also use JavaScript to do client-side validation of form values before the form is

submitted to a PHP script. Irt.org has a great tutorial - Addressing Form Field Validation with

Regular Expressions and JavaScript 1.2 that explains how to use JavaScript and regular

expressions to do form validation.

Here is an example:

JavaScript Code:


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// otherwise the string is valid

return true;

}

function isReady(form) {

if (isProper(form.firstname.value) == false) {

alert("Please enter your firstname");

form.firstname.focus();

return false;

}

return true;

}

//-->

http://onaje.com/code/jscriptcheck2.phphttp://onaje.com/code/jscriptcheck2.phpshttp://onaje.com/code/jscriptcheck2.phpshttp://onaje.com/code/jscriptcheck2.phpshttp://onaje.com/code/jscriptcheck2.phphttp://onaje.com/code/jscriptcheck2.phps

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