阿里云OSS从网页直接上传
```html
<form action="http://oss-cn-beijing.aliyuncs.com/course-xia" method="post" enctype="multipart/form-data" >
<input name="key" value="upload/xx" >
<input name="Content-Type" value="text/plain" >
<input name="OSSAccessKeyId" value="xxxxxx" >
<input name="policy" value="xxxxxx" >
<input name="Signature" value="xxxxxx" ><br>
<input type="file" name="file" >
<input type="submit" value="上传到OSS" >
</form>
```