express res.send http code and text catch up by backbone.js -

i try programming register express , backbone.js. express part looks

    app.post('/signup', function (req, res) {      var name = req.param("name", null);     var country = req.param("country", null);     var email = req.param("email", null);     var cemail = req.param("cemail", null);     var password = req.param("password", null);      if (email !== cemail ||     !validate.email(email) ||     email == null) {         console.log("there wrong email address");         res.send(400, "please check email address.");         return;     };      if (password == null || !validate.password(password)) {         console.log("there wrong password");         res.send(400, "password doesn't match security requirements");         return;     };      if (name == null || country == null) {         console.log("some fields not filled value.");         res.send(400);         return;     };      signup(name, country, email, password);     res.send(200);  });   

if user give invalid email address, gonna respond http code 400 , text. question is, how can catch text, on backbone.js site. possible or not. frontend backbone.js code

   $.post('/signup', {         name: $('input[name=name]').val(),         country: $('input[name=country]').val(),         email: $('input[name=email]').val(),         cemail: $('input[name=cemail]').val(),         password: $('input[name=password]').val()     }, function(data) {         console.log(data);     }).error(function(){         console.log("sign error");     });     return false;  

the $.post error callback passed response object , contain text error message.

.error(function(response){     console.log("sign error", response.responsetext); });