how to reply if we has seen a greeting card?

[phanbachloc]

In the greeting card sites ,for eg:www.123greetings.com,www.riversongs.com,when i send a card to my friend.When my friend has seen it,there is always a email that sent to my mailbox to inform that my friend has seen it.I do not know how can they do it?
Could you please tell me about that?
Thank you very much

[Acidic]

the email he opens is an HTML email, not plain text. this means they can have any scripts running on the email.

they run the PHP mail() function, which can send emails.

you can't see the code for this as the server runs it outputs HTML, or in this case nothing.

if you have your own server you can do this yourself, ask in the PHP section for more help.

[ober0330]

The PHP mail() call cannot be run from the email that the user receives because 9.99 out of 10 users will not have a PHP server sitting on their computer.

Those sites make the user contact the website to view their cards... when this is done, an email is sent to you and a flag is set on that card. Hence, subsequent views will not send you more notices.

So what you need to do is make the server respond to some sort of "code" that is input into your website. When that code is entered, you check the sender's email in your database, send an email to them, and then flag the order instance as being read.

[phanbachloc]

Can you tell me where can i find the source code?

[ober0330]

There is no specific source code, and it shouldn't be that hard to come up with.

Are you trying to setup a e-card site?