Saturday, 14 December 2013

How to Create a Contact Form for Your Website in an Easy Way : A Set of Step by Step Tutorials Using HTML5, CSS3 and PHP (8)

(For the latest PDF files Merger Software please have a look at the top of the left margin, inside the red box.)
Continues From Part 7
Section 1. Failure message.
Section 2. Success message.
We finished the entire code (download PHP code in Zip format here or open the code in text format here) we needed in Part (7). Now we start to understand each line. My first task is to keep the values entered into all fields as they are. That  is possible by keeping "Form inputs" of HTML parts valid and alive using PHP built-in functions.

Section 1 : How to receive contact form failure message in the same page?

First note that the form tag action is empty and won't dispatch any action to a server-side scripting page.

101 <form method="post" action="">

Next, please look at line (103) to see how PHP puts value in an HTML tag.

103 <input type="text" name="Name" id="Name" value="<?php echo isset($_POST['Name']) ? $_POST['Name'] : '' ?>" />

"echo"  is the PHP print command. Then, you can see the C language if-else style, common in many programming languages. You can put if-else if you prefer the longer style. Hence,

if (some_thing){

can be written in shorter form as,

some_thing ? do_some_job : do_else; 

PHP, used at that position, won't need the finishing semi-colon. Therefore, if the field is empty, e.g., when you first open the page, keeps it empty; otherwise, if it has some value keeps them as they are. Also there are warning and cautions accessing super-global such as $_POST['Name'] in carefully written PHP files. They need filtering functions such as using filter_input ( INPUT_POST, 'Name' ) . I avoided those details for enthusiasts in learning PHP, as I found them beyond a simple contact form. You also might like to guard fields of your form with PHP function htmlentities ( ).

Please note the difference of textarea tag. textarea is a legacy of ancient computing (I mean 1990's) and has its own specification. It accepts carriage-return, new-line, carriage-return and new-line, new paragraph, tab, Home, End, Page-Down, and Page-Up as it scrolls. These are not settled issues adding internationalisation problems to them ever increasingly. Anyway difference is not much. Value cannot be attributed  inside the tag, similar to other inputs. We put PHP code outside the tag.

115  <textarea name="Message" rows="20" cols="20" id="Message"><?php echo isset($_POST['Message']) ? $_POST['Message'] : '' ?></textarea> 

Now bring your server-side demoPoster.php file into your HTML contact form. Remember that you have saved your contact form as a PHP file with .php extension. Here I have called it demoFinal.php.

You may notice some changes from previous demoPoster.php. All the code becomes active on the condition that you "submit" the form. Otherwise when a user opens the page for the first time it will dispatch errors regarding empty fields and wrong reCaptcha. This is line (130),

130    if( isset($_POST['submit']) ) { 

and ends at line (223). 

In the next line (131) we have identified and initialised a place holder for errors of the visitor.

   $error = null; 

Call to recaptchlib.php library and introducing the "private key" is done in next two lines (132) and (133).

   $privatekey = "xxxxx-xxxxxxxxxxxxx_xxxxxxxxxxxxxxxxxxxx"; 

Logical flow here has been improved. At first stage we test if the "email" field is not empty then we test it to follow the correct format of email and we check that it originates from a really existing domain. In future, we test if the email account bounces or is notorious for spamming, then IP of the sender becomes blacklisted for our website. For now, those available tests have been moved to lines (139) to (148).

  if( !empty($Email) ){ 
                            list($emailPart, $domainPart) = explode('@', $Email);
                            $one=filter_var($Email, FILTER_VALIDATE_EMAIL);
                            if (!(($one) && ($two))) {
                                $error .= '<li>Email is invalid .</li>';
                                echo '<div id="recaptcha_fail_div"> <ul>'. $error .'</ul></div>';

For the first time, in line (144) our variable  $error  becomes filled, should the visitor's email not complying our criteria. Pay attention to PHP operator .= which adds the new error to previous value of  $error (it was  already null ). This error will be reflected in a formatted box. I have itemised it to be unified with the format of other occurring errors. Here, contact form dispatches the error and exits since it cannot accept the other fields without a valid email. Error box becomes activated by the echo command  of  PHP.  That happens in the line (145). Please have a look at this image.

Flow of the "if " test terminates the job by exit()  command in the line (146); therefore, it does not need any "else" phrase.

If the users email looks all right, then flow of the program continues to check other errors ($error at this point still is null ) for the required fields, through lines (149) to (151). Each line tests for an empty required field (remember that email already had not been checked for being empty) and in case will add one item to error box in an itemised format.

   $error .= ( empty($Name) )  ? '<li>Please enter your name.</li>' : null;
   $error .= ( empty($Email) ) ? '<li>Blank Email is not accepted.</li>' : null;
   $error .= ( empty($Message) ) ? '<li>Please enter some comments or questions.</li>' : null; 

Lines (153) to (157) get error of reCaptcha field. (It is believed reCaptcha solutions help improve artificial intelligence software that digitise scanned books and documents.) Should reCaptcha field not entered correctly then an error would be added to potential errors.

 $resp = recaptcha_check_answer ($privatekey, 
 $error .= ( !($resp->is_valid) ) ? '<li>The captcha code entered is incorrect .</li>' : null; 

Then we do check whether $error is null ( is empty) or not. Look at lines (158) to (162), please,

if (!empty($error)) {
                     // What happens when the CAPTCHA was entered incorrectly
                     echo '<div id="recaptcha_fail_div"> <ul>'. $error .'</ul></div>';

At this stage again we do not need "else" for "if" since any error terminates flow of the job. Remaining lines are already explained. Result of errors are shown in the following snapshot.

Section 2 : How to receive contact form success message in the same page?

What happens if the form and reCaptcha all filled correctly? Then you receive your "thank you" message in the same page. Line (188) to line (193) guarantee the print of "thanks" message in a desired format.

echo '<div style=\'margin-top: 20px; margin-left:112px; border: 2px groove blue; border-radius:5px; padding-left: 10px; width:400px;\'>
           <p>Thanks By <a href="">Dysprosium</a></p>
           <hr style=\'margin: 1px auto 1px auto; height: 1px; color: #fefefe; width: 82%;\'/> 
           <h1>Your message has been sent! Thanks for Your Message!</h1>
           <p><a href="Default.html">Click to go to Home page!</a></p>

 Please look at the result.
Please watch this contact form by clicking this link. In the next post I add code to get IP of the visitors and display it on the contact form.

Download this tutorial as PDF format here
Download part 1 to part 8 as PDF format here

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