PHP文件上传精简版

<?php 

if($_FILES){
	$srcname=$_FILES['headimg']['name'];
	$ext=array_pop(explode('.',$srcname));  //后缀
	$tmp=$_FILES['headimg']['tmp_name'];
	$error=$_FILES['headimg']['error'];   //错误码
	$dstdir='./public/uploads/';
	$filesize=$_FILES['headimg']['size'];  //文件大小
	$imgname=substr(md5(time().mt_rand()),3,15).'.'.$ext;
	$dst=$dstdir.$imgname;
	try {
		if($error!==0){
			$error='您没有选择上传文件';
			throw new Exception($error);
		}
		//限制大小 1M=1*1024*1024字节
		$size=1*1024*1024;	
		if($filesize>$size){
			$error = '文件大小不允许超过1M';
			throw new Exception($error);
		}
		//限制类型
		$type=array('jpg','png','gif');
		if(!in_array($ext,$type)){
			$error = '不允许该文件类型';;
			throw new Exception($error);
		}
		if(move_uploaded_file($tmp, $dst)){
			echo '文件上传成功';
		}else{
			echo '文件上传失败';
		}
	} catch (Exception $e) {
		 $error=$e->getMessage();
		echo "<script>alert('{$error}');location='index.php'</script>";
	}
}else{
	echo "<script>alert('文件大小超过php限制');location='index.php'</script>";
}
 ?>