Problem with php mail form

Hey all,
Heres the code in the first frame of my email form for a flash page. It works a treat but it will send anything and everything written in the input text boxes. Is there a way to only send if certain conditions for “email” are met, like if the @ is supplied etc.

// add the listener to the Key onj
k = new Object();
k.onKeyUp = function() {
if (Sname.text != ‘’ && Semail.text != ‘’) {
// enable btn
subscribe_mc.sendMC.sendButton.enabled = true;
} else {
// disable
subscribe_mc.sendMC.sendButton.enabled = false;
}
};
Key.addListener(k);
// set starting status
// for SEND button
subscribe_mc.sendMC.sendButton.enabled = false;
// stop on current frame
stop();

Thanks in advance!!!
CB