用css制作星级评分

Step 1: XHTML

<ul class="star-rating">   
    <li><a href="#" title="Rate this 1 star out of 5" class="one-star">1</a></li>    
    <li><a href="#" title="Rate this 2 stars out of 5" class="two-stars">2</a></li>   
    <li><a href="#" title="Rate this 3 stars out of 5" class="three-stars">3</a></li>   
    <li><a href="#" title="Rate this 4 stars out of 5" class="four-stars">4</a></li>  
    <li><a href="#" title="Rate this 5 stars out of 5" class="five-stars">5</a></li>
 </ul>

这里只介绍静态的技术，随后会给出系统的应用，你也是自己加程序来尝试一下，还可以采用ajax来做出绚丽的效果

Step 2:图像|Graphics

为了节省您的空间和宽带，我们采用gif图，这个图片就是打分的按钮。

Step 3:CSS

.star-rating{
    list-style: none; /* turn off the default list image bullets*/
    margin: 3px; /*I wan't some space around this thing*/
    padding: 0px; /* I'm anal. I'm pretty sure OL's have a default padding of 0px, but we'll set it to 0px just to be safe*/
    width: 100px; /*This list is 5 stars, each star is 20px, therefore it should be 5 x 20px = 100px wide*/
    height: 20px; /* The height of each star is 20px. Since this is a horizontal list, we will set the list height to the height of the star.*/
    position: relative; /*Very important. We will be using absolute positioning later. We want to use relatively-absolute positioning.*/
    background: url(star_rating.gif) top left repeat-x; /* By repeating this image horizontally, the list will appear to have five stars.*/
    }

根据代码我们知道：
去掉了ul的margin和padding以及list-style，定义了高20px宽100px的一个区块

下来时按钮元素的制作，下面是css

.star-rating li{
    padding:0px; /* no padding at all*/
    margin:0px; /* no margin at all*/
    /*\*/ /*Backslash hack, this causes IE5 Mac NOT to see this rule*/
    float: left; /* for any other browser, we are going to float left, this makes a horizontal list*/
    /* */ /* end the IE5 Backslash hack*/
    }

这段代码让li实现横向排放，并解决IE5 MAC bug

继承上面的按钮元素样式，再定义鼠标动作，下面是css

.star-rating li a{
    display:block; /* we want a block item, so that we can mess with its height and width*/
    width:20px; /* easy stuff, we want the width to be the same as the star width*/
    height: 20px; /* same as the width*/
    text-decoration: none; /* remove the underline from the link*/
    text-indent: -9000px; /* indent the text off the screen using a [url=http://www.mezzoblue.com/tests/revised-image-replacement/]image-replacement technique[/url], we dont want to see the text anymore.*/
    z-index: 20; /*we'll come back to this*/
    position: absolute; /*we can now control the exact x and y coordinates of each star, relative to the parent UL*/
    padding: 0px; /*once again, we don't need any padding*/
   background-image:none; /* we will not show the star*/
   }

13. .star-rating li a:hover{
  14. background: url(star_rating.gif) left bottom; /*this is where the magic is*/
  15. z-index: 1; /*move this star to the bottom of the z-index stack*/
  16. left: 0px; /*move this star all the way to the left, aligned with the side of the UL parent item*/
  17. }

下来我们要考虑怎样才能显示不同的星级，三星?四星?原理是什么，我们继续将背景图片横向重复显示，然后定义a和a:hover的宽度来区分选择的星级。

下面是css

.star-rating a.one-star{
    left: 0px;
    }  
   .star-rating a.one-star:hover{
    width:20px;
    }
   .star-rating a.two-stars{
    left:20px;
   }
   .star-rating a.two-stars:hover{
   width: 40px;
   }
   .star-rating a.three-stars{
   left: 40px;
   }
   .star-rating a.three-stars:hover{
   width: 60px;
   }
   .star-rating a.four-stars{
   left: 60px;
   }
   .star-rating a.four-stars:hover{
   width: 80px;
   }
   .star-rating a.five-stars{
   left: 80px;
   }
   .star-rating a.five-stars:hover{
   width: 100px;
   }

到此，这个制作完成

第一个模型中忽视了半星级的情况和无初始的星级，下来我们就是要解决这个问题。

Step 1. 先看看效果|Check it in action

看看效果

Step 2: The XHTML

<ul class="star-rating">
 <li class="current-rating">Currently 3.5/5 Stars.</li>
 <li><a href="#" title="1 star out of 5" class="one-star">1</a></li>
 <li><a href="#" title="2 stars out of 5" class="two-stars">2</a></li>
 <li><a href="#" title="3 stars out of 5" class="three-stars">3</a></li>
 <li><a href="#" title="4 stars out of 5" class="four-stars">4</a></li>
 <li><a href="#" title="5 stars out of 5" class="five-stars">5</a></li>
 </ul>

和第一个模型的结构相似，唯一不同的是:

<li class="current-rating">Currently 3.5/5 Stars.</li>

定义初始值

Step 3: The Star Image

我们制作一个有三个星的图片，第一个星是空值，第二个是要选择的值，第三个是真实的值。

Step 4: The CSS, the Magic

.star-rating li.current-rating{
    background: url(star_rating.gif) left bottom;
    position: absolute;
    height: 30px;
    display: block;
    text-indent: -9000px;
    z-index: 1;
    }

他定义了初始值，为了避免继承容器ul的相对定位，采用position: absolute;每个星的高度为height:30px;别的就是隐藏文本和定义对齐方式。

空值css

.star-rating{
    …
    background: url(star_rating.gif) top left repeat-x;
    }

选择值css

.star-rating li a:hover{
    background: url(star_rating.gif) left center;
    …
    }

初始值当然会随着选择变动，那么怎样实现它的变化呢?

<li class="current-rating" style="width:105px;">Currently 3.5/5 Stars.</li>

看了这段代码相信你就知道是什么原因了!那这个width是怎样计算的呢?

Average Rating|平均值: 3.5
Each Star Width|每个星的宽度: 30px;
Set width to|将宽度设为: 3.5 * 30 = 105px

下面欣赏一下这个新模型吧
* Example 1: 150 x 30 star rating system* Example 2: 125 x 25 star rating system* Example 3: 25 x 125 vertical star rating system

我们用php来实现

首先是实现的原理

从上一个css实现星级评分I 、II，可是看出，只要能识别onclick和将数据记录至数据库中存储，然后从数据库中调用出数据进行计算就
可以得到当前的评分均值——当前的分值。

1.下面是建立数据库的sql

CREATE TABLE ratings(
 id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
 total_votes INT NOT NULL,
 total_value INT NOT NULL,
 which_id INT NOT NULL,
 which_table VARCHAR(255),
 used_ips LONGTEXT NULL
 );

2.参数文件引用

<?php
require("connectDB.php");
require("closeDB.php");
require("tableName.php");
require("openDB.php");
?>

3.显示投票程序和更新投票数据程序

<?php
$rating_posted=$_GET['vote'];//pased variable by the the stars value
$id=$_GET['id'];
$query=mysql_query("SELECT total_votes, total_value, used_ips FROM $tableName WHERE id='".$id."' ")or die(" Error: ".mysql_error());
$numbers=mysql_fetch_assoc($query);
$checkIP=unserialize($numbers['used_ips']);
$count=$numbers['total_votes'];//how many votes total
$current_rating=$numbers['total_value'];//total number of rating added together and stored
$sum=$rating_posted+$current_rating;// add together the current vote value and the total vote value
$tense=($count==1) ? "vote" : "votes";//plural form votes/vote
$voted=@mysql_fetch_assoc(@mysql_query("SELECT title FROM $tableName WHERE used_ips LIKE '%".$_SERVER['REMOTE_ADDR']."%' AND id='$id' ")); //Pattern match ip:suggested by Bramus! http://www.bram.us/ - this variable searches through the previous ip address that have voted and returns true or false

if($voted){
echo "<div class=\"rating\">".
"<ul class=\"star-rating\">".
"<li class=\"current-rating\" style=\"width:". @number_format($current_rating/$count,2)*20 ."px;\">Current rating.</li>".
     "<li class=\"one-star\">1</li>".
     "<li class=\"two-stars\" >2</li>".
     "<li class=\"three-stars\">3</li>".
     "<li class=\"four-stars\">4</li>".
     "<li class=\"five-stars\">5</li>".
"</ul>".
 "<p>Rating: <strong>".@number_format($current_rating/$count,2)."</strong> {".$count." ".$tense." cast} <br />You have previously voted.</p></div>";//show the current value of the vote with the current numbers
}else{

if(isset($_GET['vote'])){

if($sum==0){
$added=0;//checking to see if the first vote has been tallied
}else{
$added=$count+1;//increment the current number of votes
}

if(is_array($checkIP)){
array_push($checkIP,$_SERVER['REMOTE_ADDR']);//if it is an array i.e. already has entries the push in another value
}else{
$checkIP=array($_SERVER['REMOTE_ADDR']);//for the first entry
}

$insert=serialize($checkIP);
mysql_query("UPDATE $tableName SET total_votes='".$added."', total_value='".$sum."', used_ips='".$insert."' WHERE id='".$_GET['id']."'");

echo  "<div class=\"rating\"><p>Rating: <strong>".@number_format($sum/$added,2)."</strong> {".$added." ".$tense." cast} <span>Thank you for your vote!</span></p></div>";//show the updated value of the vote
}else{
?>

4.访问者评分程序

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
 <head>
  <title>CSS: Star Rater Example</title>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
  <link href="styles2-1.css" rel="stylesheet" type="text/css" media="all">
 </head>
<body>
<div class="rating">
<p>How clear was this tutorial?</p>
<ul class="star-rating">
<li class="current-rating" style="width:<?php echo @number_format($current_rating/$count,2)*20 ?>px;">Current rating</li>
     <li><a href="<?php echo $_SERVER['PHP_SELF'] . "?" .$_GET['section'] . "&id=" . $_GET['id'] . "&vote=1";?>" title="Rate this 1 star out of 5" class="one-star">1</a></li>
     <li><a href="<?php echo $_SERVER['PHP_SELF'] . "?" .$_GET['section'] . "&id=" . $_GET['id'] . "&vote=1";?>" title="Rate this 2 stars out of 5" class="two-stars" >2</a></li>
     <li><a href="<?php echo $_SERVER['PHP_SELF'] . "?" .$_GET['section'] . "&id=" . $_GET['id'] . "&vote=1";?>" title="Rate this 3 stars out of 5" class="three-stars" >3</a></li>
     <li><a href="<?php echo $_SERVER['PHP_SELF'] . "?" .$_GET['section'] . "&id=" . $_GET['id'] . "&vote=1";?>" title="Rate this 4 stars out of 5" class="four-stars" >4</a></li>
     <li><a href="<?php echo $_SERVER['PHP_SELF'] . "?" .$_GET['section'] . "&id=" . $_GET['id'] . "&vote=1";?>" title="Rate this 5 stars out of 5" class="five-stars" >5</a></li>
</ul>
</body></html>

5.最新评分结果提示

<?php
echo "<p>Rating: <strong>".@number_format($sum/$count,2)."</strong> {".$count." ".$tense." cast}</p></div>";//show the current updated value of the vote
} // end isset get vote 
} //end voted true, false
?>

下一步是将结果记入数据库，现在没有时间去研究了，请大家等待下一篇文章或者去原出处阅读！