title: getting a value from mysql db and post it to php page
body: <p>i have a little problem while getting a value from database and post it to another page , heres my code . on search.php the user enter the price min and price max , then on page result.php it shows from database the name and price of the product and a link for more infos .(info.php) this 3rd page will show some additional informations based on the Id of the product shown on result.php
  i tried to hide the value of Id_product from result and post it to 3rd form but doesnt work.i got an error Notice: Undefined index: id in info.php line 4</p>
  
  <pre><code>//////search.php /////
  
  &lt;form  method="post" action="result.php" &gt; 
  &lt;tr&gt; &lt;INPUT type=text size=20 name=pricemin &gt;&lt;BR&gt;  &lt;/tr&gt;  
  &lt;tr&gt; &lt;INPUT type=text size=20 name=pricemax &gt;&lt;BR&gt;  &lt;/tr&gt;
  &lt;tr&gt; &lt;input type="submit" class="Nom" id="button" value="Valider" /&gt;&lt;/tr&gt;&lt;/form&gt;
  
  ///////result.php //////
  
  &lt;?php include 'includes/connection.php';
  $pricemin = $_POST['pricemin'];
  $pricemax = $_POST['pricemax'];
  $query = "SELECT * FROM product where price between '$pricemin' and '$pricemax'";
  $result = mysql_query($query);?&gt;
  &lt;?php if(mysql_num_rows($result) &gt; 0)
  while($products = mysql_fetch_array($result)) {?&gt;   
  &lt;?php echo $products['name_product'] ;echo $products['price_product'] ;
  echo "&lt;a href='http://localhost/mywebsite/info.php'&gt;More infos&lt;/a&gt;"
  ?&gt;
  &lt;form method="post" action="info.php" &gt;
  &lt;input type="hidden" name="id" value="&lt;?php echo $products['id_product']; ?&gt;" /&gt;
  &lt;/form&gt;&lt;?php } ?&gt;...
  
  ///// info.php //////
  
  &lt;?php
  include 'includes/connection.php';
  $id_product = $_POST['id'];
  $query = "SELECT * FROM product where id_product='$id_product'";
  $result = mysql_query($query);   ?&gt;
  &lt;html&gt;&lt;head&gt;&lt;title&gt;.. &lt;/title&gt;&lt;/head&gt;&lt;body&gt;
  &lt;?php 
  while($products = mysql_fetch_array($result)) {?&gt;
  &lt;h1&gt;Product ID : &lt;?php echo  $products['id_product'] ; ?&gt; &lt;/h1&gt;
  &lt;h1&gt;Product name : &lt;?php echo  $products['name_product'] ; ?&gt; &lt;/h1&gt;
  &lt;h1&gt;Product Qt : &lt;?php echo  $products['quantity_product'] ; ?&gt; &lt;/h1&gt;
  &lt;h1&gt;Product Spec : &lt;?php echo  $products['spec_product'] ; ?&gt; &lt;/h1&gt;
  &lt;?php } ?&gt;&lt;/body&gt;&lt;/html&gt;
  </code></pre>