Monday, September 19, 2011

Using PHP With HTML Forms

It is time to apply the knowledge you have obtained thus far and put it to real use. A very common application of PHP is to have an HTML form gather information from a website's visitor and then use PHP to do process that information. In this lesson we will simulate a small business's website that is implementing a very simple order form.
Imagine we are an art supply store that sells brushes, paint, and erasers. To gather order information from our prospective customers we will have to make a page with an HTML form to gather the customer's order.
Note: This is an oversimplified example to educate you how to use PHP to process HTML form information. This example is not intended nor advised to be used on a real business website.


If you need a refresher on how to properly make an HTML form, check out the HTML Form Lesson before continuing on.
We first create an HTML form that will let our customer choose what they would like to purchase. This file should be saved as "order.html"


order.html Code:
<html><body>
<h4>Tizag Art Supply Order Form</h4>
<form>
<select>
<option>Paint</option>
<option>Brushes</option>
<option>Erasers</option>
</select>
Quantity: <input type="text" />
<input type="submit" />
</form>
</body></html>


PHP Form Processor


We want to get the "item" and "quantity" inputs that we have specified in our HTML form. Using an associate array (this term is explained in the array lesson), we can get this information from the $_POST associative array.
The proper way to get this information would be to create two new variables, $item and $quantity and set them equal to the values that have been "posted". The name of this file is "process.php".
process.php Code:
<html><body>
<?php
$quantity = $_POST['quantity'];
$item = $_POST['item'];
echo "You ordered ". $quantity . " " . $item . ".<br />";
echo "Thank you for ordering from Tizag Art Supplies!";
?>
</body></html>
As you probably noticed, the name in $_POST['name'] corresponds to the name that we specified in our HTML form.
Now try uploading the "order.html" and "process.php" files to a PHP enabled server and test them out. If someone selected the item brushes and specified a quantity of 6, then the following would be displayed on "process.php":


Remember to review HTML Forms if you do not understand any of the above HTML code. Next we must alter our HTML form to specify the PHP page we wish to send this information to. Also, we set the method to "post".


PHP & HTML Form Review

A lot of things were going on in this example. Let us step through it to be sure you understand what was going on.
1. We first created an HTML form "order.html" that had two input fields specified, "item" and "quantity".
2. We added two attributes to the form tag to point to "process.php" and set the method to "post".
3. We had "process.php" get the information that was posted by setting new variables equal to the values in the $_POST associative array.
4. We used the PHP echo function to output the customers order.
Remember, this lesson is only to teach you how to use PHP to get information from HTML forms. The example on this page should not be used for a real business.



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