window.onload = function() {

    var User = require('/models/Mongoose Database/user_database');
    // this line is causing the problem


    var registerButton = document.getElementById("registerMe");
    var firstName = document.getElementById("firstName");
    var lastName = document.getElementById("lastName");
    var usernameRegister = document.getElementById("usernameRegister");
    var passwordRegister = document.getElementById("passwordRegister");
    var repasswordRegister = document.getElementById("repasswordRegister");


    registerButton.onclick = function () {

       if(!firstName.value || !passwordRegister.value || !repasswordRegister.value || !usernameRegister.value){
           alert("Enter all required fields");
       }else if (passwordRegister.value != repasswordRegister.value){
            alert("Passwords must match");
       }else {
           var newUser = new User({
                       username : usernameRegister.value,
                       password : passwordRegister.value
                   });
               User.find({username:usernameRegister.value}, function (error, user) {

                       if (error) throw error;

                       if(user){
                           window.location("/register");
                       }else {
                           newUser.save(function (error) {
                               if(error) throw error;
                           });
                           window.location("/login");
                       }
                       // user.comparePassword(passwordRegister.value, function (error, isMatch) {
                       //     if (error) throw error;
                       //
                       //     return 1;

                       //})
               });

       }

    }


}