$ cat pv.html

<!DOCTYPE html>
<html>
<body>

<form action="upload.php" method="post" enctype="multipart/form-data">
    Select image to upload:
    <input type="file" name="fileToUpload" id="fileToUpload">
    <input type="submit" value="Upload Image" name="submit">
</form>

</body>
</html>


$ cat upload.php

<?php
$target_dir = "/var/www/uploads/";
$target_file = $target_dir . basename($_FILES["fileToUpload"]["name"]);
$uploadOk = 1;
$imageFileType = pathinfo($target_file,PATHINFO_EXTENSION);

echo "The value of target directory is =" . $target_dir . "</br>";
echo "The value of target file is      =" . $target_file . "</br>";
echo "The value of uploadOk is         =" . $uploadOk . "</br>";
echo "The value of imageFileType is    =" . $imageFileType . "</br>";

echo "Upload: " . $_FILES["fileToUpload"]["name"] . "<br />";
echo "Type: " . $_FILES["fileToUpload"]["type"] . "<br />";
echo "Size: " . ($_FILES["fileToUpload"]["size"] / 1024) . " Kb<br />";
echo "Temp file: " . $_FILES["fileToUpload"]["tmp_name"] . "<br />";
echo "Error :" . $_FILES["fileToUpload"]["error"] . "<br / >";


    if (move_uploaded_file($_FILES["fileToUpload"]["tmp_name"], $target_file)) {
        echo "The file ". basename( $_FILES["fileToUpload"]["name"]). " has been uploaded.";
    } else {
        echo "Sorry, there was an error uploading your file.";
    }

$finfo = finfo_open(FILEINFO_MIME_TYPE);

echo "</br> The value of finfo is =" . $finfo . "</br>";
echo finfo_file($finfo, $target_file );
finfo_close($finfo);

?>


Reference


http://php.net/manual/en/features.file-upload.php


To find out error codes.

http://php.net/manual/en/features.file-upload.errors.php