Originally Posted by drumthrasher109
I'm not sure...
To check, go to Gmail on a desktop browser - go to Settings > Forwarding & POP/IMAP - and look at IMAP status - see if it has Enabled or Disabled selected.
If you are using IMAP, your mail folders (incl. Inbox) should stay in sync between iPhone / browser etc.
If you don't fancy IMAP, you also have settings on that page for how messages are treated when they're accessed via POP etc.