<button type="button" class="btn btn-primary btn-lg" data-toggle="modal" data-target="#myModal">
  Log In/Sign Up
</button>

<!-- Modal -->
<div class="modal fade" id="myModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel">
  <div class="modal-dialog" role="document">
    <div class="modal-content">
      <div class="modal-header">
        <button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">&times;</span></button>
        <h4 class="modal-title" id="myModalLabel">Have an Account?</h4>
      </div>
      <div class="modal-body">
        <ul class="nav nav-tabs">
        <li class="active"><a href="#login" data-toggle="tab">Login</a></li>
        <li><a href="#create" data-toggle="tab">Create Account</a></li>
      </ul>
      <div class = "tab-content" id = "myTabContent">
        <div class="tab-pane active in" id="login">
          <h3> Login </h3>
          <div>
            Username: <input placeholder = "Username" \>
          </div>
          <div>
            Password: <input placeholder = "Password" \>
          </div>
        </div>
        <button type="button" class="btn btn-success btn-lg" data-dismiss="modal">Close</button>

        <div class="tab-pane fade" id="create">
          This is the create account page
        </div>
      </div>

      </div>

    </div>
  </div>
</div>