Do a picture upload function, always prompt two lines of exception

Do a picture upload function, always prompt two lines of error.
Do a picture upload function, always prompt two lines of error:
notice:undefined index:upload in D:\WWW\qiangyuan\up.php on line 34
notice:undefined index:upload in D:\WWW\qiangyuan\up.php on line 41



The code is as follows:









/**
* $file _ext: Upload the file image format;
* $file _name: After uploading, there is a new path and file name on the server;
*/

$file _ext = $_files["Upload" ["name"];
$file _ext_rev = Strrev ($file _ext);
$file _ext_num = Strrpos ($file _ext_rev, ".");
$file _ext = Strrev ($file _ext_rev);
$file _ext = substr ($file _ext,-$file _ext_num);
$file _ext = strtolower ($file _ext);

if ($_files["Upload" ["size"] > 0)
{
Limit the uploaded file format
if ($file _ext = = = "JPG" | | $file _ext = = "JPEG" | | $file _ext = = "gif" | | $file _ext = = "png")
{
if ($_files["Upload" ["Size"] < 400000)//Picture size cannot be greater than
{
$file _name = "./". Date ("Ymdhis");
$file _name. = ".". $file _ext;

$tmp _name = $_files["Upload" ["tmp_name"];
Move_uploaded_file ($tmp _name, "product/$file _name"); Upload to Picture directory

Echo substr ($file _name,2);//output generated picture name

echo "

";
echo "";

}
Else
{
echo "Upload file image size must be less than 400kb";
}
}
Else
{
echo "uploaded file format is incorrect";
}
}
?>



------Solution--------------------
discuss
Do a picture upload function, always prompt two lines of error:
notice:undefined index:upload in D:\WWW\qiangyuan\up.php on line 34
notice:undefined index:upload in D:\WWW\qiangyuan\up.php on line 41



The code is as follows:




------Solution--------------------
Judge $_files[' upload ' [' error '] = = ' 0 ' to see if it has been uploaded to PHP.

You can also print_r before using $_files ($_files); View the parameters.
------Solution--------------------
Explore

To determine whether the form has been submitted, if there are files uploaded and then processed:

PHP Code
if (isset ($_files[' upload ')} {
$file _ext = $_files["Upload" ["name"];
$file _ext_rev = Strrev ($file _ext);
$file _ext_num = Strrpos ($file _ext ...

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