在PHP中使用內(nèi)置的`$_FILES`全局變量來獲取上傳文件的信息。當(dāng)你通過HTML表單提交個(gè)文件時(shí)，這個(gè)文件就會(huì)被發(fā)送到服務(wù)器，且在這個(gè)變量中訪問。

```html

Select image to upload:

```

```php

$target_dir = "uploads/";

$target_file = $target_dir . basename($_FILES["fileToUpload"]["name"]);

$imageFileType = strtolower(pathinfo($target_file,PATHINFO_EXTENSION));

// Check if image file is a actual image or fake image

if(isset($_POST["submit"])) {

$check = getimagesize($_FILES["fileToUpload"]["tmp_name"]);

if($check !== false) {

echo "File is an image - " . $check["mime"] . ".";

$uploadOk = ;

} else {

echo "File is not an image.";

$uploadOk = ;

}

}

// Check if file already exists

if (file_exists($target_file)) {

echo "Sorry, file already exists.";

$uploadOk = ;

}

// Check file size

if ($_FILES["fileToUpload"]["size"] > ) {

echo "Sorry, your file is too large.";

$uploadOk = ;

}

// Allow certain file formats

if($imageFileType != "jpg" && $imageFileType != "png" && $imageFileType != "jpeg"

&& $imageFileType != "gif" ) {

echo "Sorry, only JPG, JPEG, PNG & GIF files are allowed.";

$uploadOk = ;

}

// Check if $uploadOk is set to by an error

if ($uploadOk == ) {

echo "Sorry, your file was not uploaded.";

// if everything is ok, try to upload file

} else {

if (move_uploaded_file($_FILES["fileToUpload"]["tmp_name"], $target_file)) {

echo "The file ". htmlspecialchars( basename( $_FILES["fileToUpload"]["name"])). " has been uploaded.";

} else {

echo "Sorry, there was an error uploading your file.";

}

}

?>

```