PHP Tutorial Part 10

The getVote() Function
This function executes when "yes" or "no" is selected in the HTML form.

1.    Defines the url (filename) to send to the server

2.    Adds a parameter (vote) to the url with the content of the input field

3.    Adds a random number to prevent the server from using a cached file

4.    Calls on the GetXmlHttpObject function to create an XMLHTTP object, and tells the object to execute a function called stateChanged when a change is triggered

5.    Opens the XMLHTTP object with the given url.

6.    Sends an HTTP request to the server

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The PHP Page

The server page called by the JavaScript code is a simple PHP file called "poll_vote.php".

<?php $vote = $_REQUEST['vote']; //get content of textfile $filename = "poll_result.txt"; $content = file($filename); //put content in array $array = explode("||", $content[0]); $yes = $array[0]; $no = $array[1]; if ($vote == 0) { $yes = $yes + 1; } if ($vote == 1) { $no = $no + 1; } //insert votes to txt file $insertvote = $yes."||".$no; $fp = fopen($filename,"w"); fputs($fp,$insertvote); fclose($fp); ?> <h2>Result:</h2> <table> <tr> <td>Yes:</td> <td> <img src="poll.gif" width='<?php echo(100*round($yes/($no+$yes),2)); ?>' height='20'> <?php echo(100*round($yes/($no+$yes),2)); ?>% </td> </tr> <tr> <td>No:</td> <td> <img src="poll.gif" width='<?php echo(100*round($no/($no+$yes),2)); ?>' height='20'> <?php echo(100*round($no/($no+$yes),2)); ?>% </td> </tr> </table>

The selected value is sent from the JavaScript and the following happens:

1.    Get the content of the "poll_result.txt" file

2.    Put the content of the file in variables and add one to the selected variable

3.    Write the result to the "poll_result.txt" file

4.    Output a graphical representation of the poll result

                                                                     THANK YOU 

                                                                      THAMARAI