For html emails, what content appears in the e-mail preview?

Question

In certain e-mail clients (such as iOS mail), a number of lines of the e-mail appear in your inbox before you open the e-mail. For text e-mails, these are probably the first 1-4 lines; however, for html emails, what content appears?

I know that each e-mail client is different, but in general (like for gmail and iOS mail), what is selected? I've tried doing a few tests, but haven't been able to determine a pattern.

Answer 1

It depends on the client but they generally convert HTML to text (forget all tags) and take the first lines of that. That's the reason you sometimes get "Your client doesn't support HTML e-mails" in the preview - this error line is usually the first text in the e-mail.