Will the label (red,..) attribute gets lost after move files from Mac to WIndows and then move back

Since Windows doesn't support label in file attributes, will this information be ripped off?

In addition, what happens if I upload a labelled开发者_运维知识库 file to the internet and then download it back? would the attributes go missing?

It depends on how you do the moving, and whether you move it back by the same (/similar enough) method. Here are some examples:

1. If you move it to a Windows file server (running on an NTFS volume) over the SMB protocol, the Mac-only metadata (labels and such) will be stored an an NTFS alternate data stream on the server; if you copy it back the same way, the metadata will be recovered and reattached.

2. If you move it to something like a FAT32 format keychain drive, it'll be stored as two files: a regular file with the file's data contents, and a second AppleDouble file with "._" as a filename prefix, containing all the Mac-only metadata. Note that if you moved the file to Windows using a method that encodes this way, and moved back by method #1, the metadata would be in the wrong format and would get lost; the same would happen if you reversed the order.

3. If you upload it with something like a web form, I'm pretty sure the metadata will not be sent at all. Similarly, if you download something from a web site, it won't look for ._ files or alternate data streams, so even if the metadata is on the web server, it won't get downloaded. (Unless you store it on the server in something like MacBinary format...)