php - upload a file form - doesn't recognize the $_FILES variable -

i've got following form:

<form method="post" action="index.php">     product name:     <input type="text" name="product_name" value="<?php echo $product_name;?>"/>     <br /> <br />     product details     <textarea rows = "6" cols = "30" name="product_details" > <?php echo $product_details;?></textarea>     <br /> <br />     product price     <input type="text" name = "product_price" value="<?php echo $product_price;?>"/>     <br /> <br />     cn:     <input type="text" name = "product_cn" value="<?php echo $product_cn;?>"/>     <br /> <br />     image     <input type="file" name="filefield" />     <br /> <br />      <input type="submit" name="submit" value="register product" /> </form> 

my problem is, whenever try process image using code:

move_uploaded_file($_files['filefield']['tmp_name'], "../product_images/$newname"); 

i following error:

notice: undefined index: filefield

why that?

thanks in advance!

you have add enctype='multipart/form-data' form
quote topic this

when make post request, have encode data forms body of request in way.

html forms provide 2 methods of encoding. default application/x-www-form-urlencoded, more or less same query string on end of url. other, multipart/form-data, more complicated encoding 1 allows entire files included in data.