如何在TextAreaField中使用jQuery和Flask-WTF进行实时字数统计？

<form>
  {{ form.text_area(id='myTextArea') }}
</form>

<script>
  $(document).ready(function() {
    $('#myTextArea').on('input', function() {
      var text = $(this).val();
      var count = text.length;
      $('#charCount').text(count);
    });
  });
</script>

<p>字符数: <span id="charCount">0</span></p>

from flask import Flask, render_template
from flask_wtf import FlaskForm
from wtforms import TextAreaField

app = Flask(__name__)
app.config['SECRET_KEY'] = 'your-secret-key'

class MyForm(FlaskForm):
    text_area = TextAreaField('Text')

@app.route('/', methods=['GET', 'POST'])
def index():
    form = MyForm()
    if form.validate_on_submit():
        # 处理表单提交逻辑
        pass
    return render_template('index.html', form=form)

if __name__ == '__main__':
    app.run()