建设一个简单交互的网站(五)
8. 投票系统
在许多时候，我们需要收集上网者和网友们的意见。例如：新版页面与旧版页面的比较；对某一事情的看法；对体育比赛结果的预测等等。这时候，你需要一个非常有效的网上调查系统。使用PHP就可以非常方便地实现你的这一构想。
8.1 投票系统（mypolls.php3）：
<?$status=0;if(isset($polled)&&($polled=="c-e")){$status=1;}#echo "$status";if(isset($poll)&&($status==0)){setcookie("polled","c-e",time()+86400,"/");#time=24h}?><html><head><title>新版页面调查</title><meta http-equiv="Content-Type" content="text/html; charset=gb2312"><style type="text/css"><!--.tb { border="1" bordercolor="#009933" cellspacing="0" font-size: 9pt; color: #000000}.head { font-family: "宋体"; font-size: 12pt; font-weight: bold; color: #009933; text-decoration: none}.pt9 { font-size: 9pt}a.p9:link { font-size: 9pt; color: #000000; text-decoration: none}a.p9:visited { font-size: 9pt; color: #000000; text-decoration: none }a.p9:hover { font-size: 9pt; color: #FF0000; text-decoration: underline}a.p9:active { font-size: 9pt; color: #FF0000; text-decoration: underline }--></style></head><body bgcolor="#FFFFFF"><div class="head">与旧版页面相比较您觉得新版页面：</div><br><?if(!isset($submit)){?><form action="myPolls.php3" method="get"><input type="radio" name="poll_voteNr" value="1" checked ><span class="pt9">信息量更大</span> <br><input type="radio" name="poll_voteNr" value="2" ><span class="pt9">网页更精美</span> <br><input type="radio" name="poll_voteNr" value="3" ><span class="pt9">没什么改进</span> <br><input type="radio" name="poll_voteNr" value="4" ><span class="pt9">其它</span> <br><input type="submit" name="submit" value="OK"><input type="hidden" name="poll" value="vote"><A HREF="myPolls.php3?submit=OK" class="p9">查看调查结果</A></form><?/*如果想增加其它的选项可直接加上即可*/}else{$descArray=array(1=>"信息量更大",2=>"网页更精美",3=>"没什么改进",4=>"其它");$poll_resultBarHeight = 9; // height in pixels of percentage bar in result table$poll_resultBarScale = 1; // scale of result bar (in multiples of 100 pixels)$poll_tableHeader="<table border=1 class="tb">";$poll_rowHeader="<tr>";$poll_dataHeader="<td align=center>";$poll_dataFooter="</td>";$poll_rowFooter="</tr>";$poll_tableFooter="</table>";$coutfile="data.pol";$poll_sum=0;// read counter-fileif (file_exists( $coutfile)){$fp = fopen( $coutfile, "rt");while ($Line = fgets($fp, 10)){// split lines into identifier/counterif (ereg( "([^ ]*) *([0-9]*)", $Line, $tmp)){$curArray[(int)$tmp[1]] = (int)$tmp[2];$poll_sum+=(int)$tmp[2];}}// close filefclose($fp);}else{//for ($i=1;$i<=count($descArray);$i++){$curArray[$i]=0;}}if(isset($poll)){$curArray[$poll_voteNr]++;$poll_sum++;}echo $poll_tableHeader;// cycle through all options编历数组reset($curArray);while (list($K, $V) = each($curArray)){$poll_optionText = $descArray[$K];$poll_optionCount = $V;echo $poll_rowHeader;if($poll_optionText != ""){echo $poll_dataHeader;echo $poll_optionText;echo $poll_dataFooter;if($poll_sum)$poll_percent = 100 * $poll_optionCount / $poll_sum;else$poll_percent = 0;echo $poll_dataHeader;if ($poll_percent > 0){$poll_percentScale = (int)($poll_percent * $poll_resultBarScale);}printf(" %.2f %% (%d)", $poll_percent, $poll_optionCount);echo $poll_dataFooter;}echo $poll_rowFooter;}echo "总共投票次数:<font color=red> $poll_sum</font>";echo $poll_tableFooter;echo "<br>";echo "<input type="submit" name="Submit1" value="返回主页" onClick="javascript:location='http://gophp.heha.net/index.html'">";echo " <input type="submit" name="Submit2" value="重新投票" onClick="javascript:location='http://gophp.heha.net/mypolls.php3'">";if(isset($poll)){// write counter file$fp = fopen($coutfile, "wt");reset($curArray);while (list($Key, $Value) = each($curArray)){$tmp = sprintf( "%s %dn", $Key, $Value);fwrite($fp, $tmp);}// close filefclose($fp);}}?></body></html>
注释：从上面我们可以看出该投票系统的基本过程：
1、打开文件取得数据到数组$curArray（文件不存在则初始化数组$curArray）
2、编历数组，处理数据得到所需值
3、计算百分比，控制统计bar图像宽度
4、将数据保存到"data.pol"中
这里有一点是需要注意：这里的data.pol文本文件需要有写权限。
