I have seen some mails which has HTML content embedded in them. The content of the mail changes as the corresponding webpage in their site change(for example price of stocks which keeps updating in the mail itself). How to link such webpage content into emails? In other words how to link a web page into an email so that whenever I change the html page, the mail content also changes. Thanks...
You could place an image in your HTML - which was updated by you on your server.
This may be impossible due to security limitations, but you may be able to use an iframe element.
A thought: maybe they are using an image that is downloaded from the server?
As you can't have JavaScript in an email or even most CSS, I'm guessing this might be one of the only ways. I'm pretty sure that one email client or service removes every piece of "special" HTML: iframes, JavaScript, CSS, Flash, etc.
Not a solution, but a quick answer from my site on this topic as a user: Beside the point that Javascript/Image/IFrame/Flash solutions doesn't reliable work in all email clients, but are a general security risk, I dislike the basic idea of changing the looks of an email after you have send it without the receivers approval. Additionally you make it very easy for the user to be tracked (working hours, locations, view) and that is definitely NOT in the interest of the users. If you have something important or interesting to tell just provide a link to your site plus a short description...