一个简单的利用POST方法上传文件

请选择您要上传的文件：
<form method="post" action ="index.php" enctype="multipart/form-data">
<input type="hidden" name="action" value='upload' />
<input type="file" name="u_file" />
<input type="submit" value="上传" />
<form>
<?php
$date=md5(time());
if($_POST[action]=="upload"){
if($_FILES[u_file][size]>"300000"){
echo "文件上传过大，请重新选择!";
}else if($_FILES[u_file][tmp_name]){
move_uploaded_file($_FILES[u_file][tmp_name],
"./mkbook//$date".$_FILES[u_file][name]);
echo "文件上传成功";
}else{
echo "文件上传失败";
}
}
?>