Demo about AJAX voting-PHP Tutorial-php.cn

Demo about AJAX voting

jacklove

Release： 2023-03-25 14:44:01

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Demonstrates a voting program through which the voting results are displayed without refreshing the web page. This article will demonstrate the effect of voting.

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>菜鸟教程(runoob.com)</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>

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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 (containing 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[&#39;vote&#39;]);// 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>

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

Get the contents of the "poll_result.txt" file

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

Write the results to the "poll_result.txt" file

Output graphical voting results

Text file

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

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).