1、主页：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<form method="post" action="upload.php" enctype="multipart/form-data">
<input type="file" name="file">
<input type="submit" value="上传">
</form>
</body>
</html>
2、处理页面：
<?php
$types = ['image/jpeg','image/png'];
//in_array()
if(!$_FILES['file']['error']){
if(in_array($_FILES['file']['type'],$types) ){
if($_FILES['file']['size']<2000000){
$file_name = "./upload/".'123'.$_FILES['file']['name'];
if(!file_exists($file_name)) {
move_uploaded_file($_FILES['file']['tmp_name'], $file_name);
}else{
echo "文件已存在";
}
}else{
echo "文件过大";
}
}else{
echo "格式不符合要求";
}
}else{
echo "上传失败";
}