<form method="post" action="/mockservice" method = "post">
   ... 

  <div class="form-group">
    <label>data <font style="color:#a94442" size="2">
    <input class="form-control" id="data" name="data">
  </div>
  <div class="form-group">
    <button id="start" type="submit" class="btn btn-default">Submit &nbsp</button>
  </div>
</form> 

$(document).ready(function() {
  MockTask.start();
});

MockTask ={
  startId: "start_mock",
  start: function(){
    $('#'+this.startId).click(function (){
　　　　　　　　...var data = $('#data').val();

      var form_data = JSON.stringify({
       ..."data": data
      });
      MockSubmit.createTask(form_data);

    });
  },
};

MockSubmit = {
  createTask: function(data){
    var url = "/mockservice";
    $.post(url,data,function(result){
      if (result.code != 'SUCC'){
        alert("failed to create a new api.")
      } else {
        alert("succ");
      }
    });
  }
};

function isEmptyString(info) {
  if (info == null || info == undefined || info.length == 0){
    return true;
  }
  return false
} 

@app.route("/mockservice",methods=['GET','POST'])
def MockController():
  form = MockCreate()
  if request.method == 'POST':
    code = request.form['code']
    api = request.form['api']
  return ... 

<form method="post" action="/mockservice" method = "post">
   ...

  <div class="form-group">
    <label>data <font style="color:#a94442" size="2">
    <input class="form-control" id="data" name="data">
  </div>
  <div class="form-group">
    <button type="submit" class="btn btn-default">Submit &nbsp</button>
  </div>
</form>

class MockCreate(Form):
  user_email = StringField("email address",[validators.Email()])
  api = StringField("api",[Required()])
  submit = SubmitField("Submit")
  code = IntegerField("code example: 200",[Required()])
  alias = StringField("alias for api")
  data = TextAreaField("json format",[Required()])

@app.route("/mockservice",methods=['GET','POST'])
def MockController():
  form = MockCreate()
  code = form['code']
  api = form['api']
  return render_template("testf.html",api=api,data=code)