在添加到数据库之前在django表单上执行Javascript函数

# forms.py
from django import forms

class MyForm(forms.Form):
    my_field = forms.CharField()

# views.py
from django.shortcuts import render
from django.http import JsonResponse

def my_view(request):
    if request.method == 'POST':
        form = MyForm(request.POST)
        if form.is_valid():
            my_field_value = form.cleaned_data['my_field']
            # 将my_field_value添加到数据库中
            return JsonResponse({'success': True})
        else:
            return JsonResponse({'success': False, 'errors': form.errors})
    else:
        form = MyForm()
    return render(request, 'my_template.html', {'form': form})

<!-- my_template.html -->
<form id="myForm" method="post" action="{% url 'my_view' %}">
  {% csrf_token %}
  {{ form }}
  <button type="submit">提交</button>
</form>

<script>
  document.getElementById('myForm').onsubmit = function() {
    // 执行JavaScript函数
    var myFieldValue = document.getElementById('id_my_field').value;
    // 进行数据处理
    // ...
    // 使用AJAX发送数据到后端
    var xhr = new XMLHttpRequest();
    xhr.open('POST', '{% url 'my_view' %}', true);
    xhr.setRequestHeader('Content-Type', 'application/json');
    xhr.onreadystatechange = function() {
      if (xhr.readyState === 4 && xhr.status === 200) {
        var response = JSON.parse(xhr.responseText);
        if (response.success) {
          // 处理成功
        } else {
          // 处理失败
        }
      }
    };
    xhr.send(JSON.stringify({my_field: myFieldValue}));
    return false; // 阻止表单的默认提交行为
  };
</script>