AJAX Voting
In the following example, we will demonstrate a voting program through which the voting results are displayed without refreshing the web page. show.
Do you like PHP and AJAX?
Yes:
No:
Example explanation - 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:
1) Create XMLHttpRequest object
2) Create Function executed when the server response is ready
3) Send a request to the file on the server
4) 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 above through JavaScript 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:
1) Get the contents of the "poll_result.txt" file
2) Put the file contents into a variable, And add 1 to the selected variable
3) Write the result to the "poll_result.txt" file
4) Output the graphical voting result
Text file
The text file (poll_result.txt) stores data from the voting program.
The data it stores is as follows:
3||4
The first number represents the number of votes for "Yes" , the second number represents the number of "No" votes.
Note: Please remember to only allow your web server to edit this text file. Don't let anyone else gain access except the web server (PHP).
Next Section