It is do-able on the server side.
<button type="submit" name="signin" value="email_signin" action="/signin">Sign In</button>
<button type="submit" name="signin" value="facebook_signin" action="/facebook_login">Facebook</button>
and in my node server side script
app.post('/', function(req, res) {
if(req.body.signin == "email_signin"){
function(email_login) {...}
}
if(req.body.signin == "fb_signin"){
function(fb_login) {...}
}
});