純用 javascript post form

const createElement = (node, attrs) => {
  const el = document.createElement(node)
  const setAttr = (attr) => el.setAttribute.call(el, ...attr)
  Object.entries(attrs).forEach(setAttr)
  return el
}

const createForm = (url) => createElement('form', {
  action: url,
  method: 'POST',
  style: 'display: none'
})

const createField = (name, value) => createElement('input', {
  type: 'hidden',
  name: name,
  value: value
})

const postJSON = (url, obj) => {
  const form = createForm(url)
  Object.entries(obj).forEach(([name, value])=> {
    if (!Array.isArray(value)) {
      value = [value]
    }
    value.forEach((val)=>{
      form.appendChild(createField(name, val))
    })
  })

  document.body.appendChild(form)
  form.submit()
  document.body.removeChild(form)
}