I hardly think protecting users of my site from spam is "complicating things from nothing". I think most people would agree with me, too.
How exactly would I do it with document.write? I can't just write a link in a popup window because then the person would have to click twice: once to open the window and the second to send the email. That's not very good user interface design and is a hassle to the user. I don't mind things being a hassle to code if it makes it easier for the user but that is not the case obviously. Unless you are suggesting something else that I am missing?
I just want to have a script that decodes an argument (the email address) and causes the email client to start an email with the address already filled in, just like a mailto link does.
I'm guessing this can't be done though unless there is some sort of header("Mailto: someone@somewhere.com") type of thing I can do (what I was originally asking) and since (thankfully) I can't execute programs such as the mail program on the client side of things.