In short NO not directly from the client (excluding hacks).
you could make an ajax call to your server and send an email.
the problem with doing it from the client and not using a mail client is complicated. For example most consumer ISPs have their own SMTP relay that all outbound mail on port 25 must be transmitted over. You website will have trouble obtaining the proper information to do this. Secondly the webbrowser doesn't understand the SMTP protocol and neither does the XMLHttpRequest object.
So if you are a hacker ninja, maybe you can figure something out with ActiveX, Java Applets, or flash, but you basically would have to be operating directly with a tcp socket and issuing SMTP protocol commands over that socket.
There are many obstacles to overcome, in fact I don't know how to do it, but where there is will there is a way. Don't be surprised that if you do find a hack, it may be plugged swiftly by the major browser vendors.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…