下拉列表不起作用

<!--Form to make above array into dropdown-->   
        <html xmlns:o="urn:schemas-microsoft-com:office:office"
        xmlns:x="urn:schemas-microsoft-com:office:excel">
        <html>
        <head>
        <title></title>
        <meta http-equiv="Content-type" content="text/html;charset=utf-8" />
        </head>
        <body>
            <?php     
            $f=mysql_query("show tables from emc");  
            ?>
    <form action="" method="GET">
    <select name="col">
    <option value="">- COLUMN NAME -</option>
          <?php  while($row=mysql_fetch_assoc($f)) {
       foreach($row as $k =>$vv)  {?>
       <option name=<?='$vv'?>><?=$vv?></option>
           <?php   }?>
           <?php   }?>              
           </select>
           <input type="SUBMIT" value="SUBMIT">
           <?php   ?>           
          </form>
         </body>
    </html>

I solve my problem and now its working fine . I was using mysql_fetch_array instead for mysql_fetch_assoc. it was showing me two values but by using assoc , its showing me the result which i want

Use mysql_fetch_assoc() to get just an associative array which will end the double-output issue.