Spam email getting on iPhone even though blocked on computer

Sounds like your email program has SPAM filters set in it.
The iPhone is connecting to your mail server, thus gets what is on the mail server.
Your home computer does the same but then filters as it comes in with spam software/filters (however you have it setup)

For me, my spam filters are set on my mail server itself so spam is filtered out before any computer/device even checks for mail, thus I don't get spam on my computer or on my phone.

Consider a mail service that filters spam at the server level.

It appears that you are accessing your email directly from the server, i.e. webmail. I use Gmail as well and access it via webmail from a desktop and my iPhone. The little spam I do get goes to the default Gmail Spam folder. It does not get to my Inbox, either when viewed via webmail or my iPhone.

Is the spam being blocked or just pulled down and deleted by your iPhone? Have you tried using the Gmail filters? You may try deleting the account on your iPhone and re-setting up.

ditto,

I use yahoo biz webmail and I get about four spam emails a day ONLY on the iPhone. These messages do not appear when I log-in to the online web interface from my mac book pro. ???