PHP Example - AJAX Poll

PHP Example - AJAX Voting

AJAX Voting

In the following example, we will demonstrate a voting program, through which the voting results are not carried out on the web page Displayed when refreshed.

QQ图片20161010104701.png

Explanation of examples - HTML page

When the user selects one of the above options, a function named "getVote()" will be executed. This function is triggered by the "onclick" event.

poll.html file code is as follows:

<html>
<head>
<meta charset="utf-8">
<title>php中文网(php.cn)</title>
<script>
function getVote(int) {
  if (window.XMLHttpRequest) {
    // IE7+, Firefox, Chrome, Opera, Safari 执行代码
    xmlhttp=new XMLHttpRequest();
  } else {
    // IE6, IE5 执行代码
    xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
  }
  xmlhttp.onreadystatechange=function() {
  if (xmlhttp.readyState==4 && xmlhttp.status==200)
    {
      document.getElementById("poll").innerHTML=xmlhttp.responseText;
    }
  }
  xmlhttp.open("GET","poll_vote.php?vote="+int,true);
  xmlhttp.send();
}
</script>
</head>
<body>
<div id="poll">
<h3>你喜欢 PHP 和 AJAX 吗?</h3>
<form>
是:
<input type="radio" name="vote" value="0" onclick="getVote(this.value)">
<br>否:
<input type="radio" name="vote" value="1" onclick="getVote(this.value)">
</form>
</div>
</body>
</html>

getVote() function will perform the following steps:

Create XMLHttpRequest object

Created when the server response is ready The executed function

Sends a request to the file on the server

Please note the parameter (q) added to the end of the URL (contains the contents of the drop-down list)

PHP file

The server page called by JavaScript above is a PHP file named "poll_vote.php":

<?php
$vote = htmlspecialchars($_REQUEST['vote']);
// 获取文件中存储的数据
$filename = "poll_result.txt";
$content = file($filename);
// 将数据分割到数组中
$array = explode("||", $content[0]);
$yes = $array[0];
$no = $array[1];
if ($vote == 0)
{
  $yes = $yes + 1;
}
if ($vote == 1)
{
  $no = $no + 1;
}
// 插入投票数据
$insertvote = $yes."||".$no;
$fp = fopen($filename,"w");
fputs($fp,$insertvote);
fclose($fp);
?>
<h2>结果:</h2>
<table>
  <tr>
  <td>是:</td>
  <td>
  <span style="display: inline-block; background-color:green;
      width:<?php echo(100*round($yes/($no+$yes),2)); ?>px;
      height:20px;" ></span>
  <?php echo(100*round($yes/($no+$yes),2)); ?>%
  </td>
  </tr>
  <tr>
  <td>否:</td>
  <td>
  <span style="display: inline-block; background-color:red;
      width:<?php echo(100*round($no/($no+$yes),2)); ?>px;
      height:20px;"></span>
  <?php echo(100*round($no/($no+$yes),2)); ?>%
  </td>
  </tr>
</table>

When the selected value is sent from JavaScript to the PHP file, what will happen:

Get the contents of the "poll_result.txt" file

Put the file contents into the variable and add 1 to the selected variable

Write the result to the "poll_result.txt" file

Output graphical voting results

Text file

The text file (poll_result.txt) stores the data from the voting program.

The data it stores is as follows:

3||4

The first number represents the number of votes for "Yes", and the second number represents The number of "No" votes.

Note: Please remember to allow only your web server to edit this text file. Don't let anyone else gain access except the web server (PHP).

Continuing Learning

new file

<html> <head> <meta charset="utf-8"> <title>php中文网(php.cn)</title> <script> function getVote(int) { if (window.XMLHttpRequest) { // IE7+, Firefox, Chrome, Opera, Safari 执行代码 xmlhttp=new XMLHttpRequest(); } else { // IE6, IE5 执行代码 xmlhttp=new ActiveXObject("Microsoft.XMLHTTP"); } xmlhttp.onreadystatechange=function() { if (xmlhttp.readyState==4 && xmlhttp.status==200) { document.getElementById("poll").innerHTML=xmlhttp.responseText; } } xmlhttp.open("GET","poll_vote.php?vote="+int,true); xmlhttp.send(); } </script> </head> <body> <div id="poll"> <h3>你喜欢 PHP 和 AJAX 吗?</h3> <form> 是: <input type="radio" name="vote" value="0" onclick="getVote(this.value)"> <br>否: <input type="radio" name="vote" value="1" onclick="getVote(this.value)"> </form> </div> </body> </html>

submit Reset Code

Automatic operation

PHP Example - AJAX Poll

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