JSONP

jsonp.js

function merge () {
  var args = [].slice.call(arguments)
  var obj = {}
  args.forEach(function (arg) {
    if (typeof arg === 'object' && arg) {
      for (var k in arg) {
        obj[k] = arg[k]
      }
    }
  })
  return obj
}

function serialize (obj) {
  var spans = []
  for (var k in obj) {
    spans.push(k + '=' + obj[k])
  }
  return spans.join('&')
}

function jsonp (options) {
  var script = document.createElement('script')
  var callbackFn = options.callback || ('jsonpCallback' + Math.random()).replace('0.', '')
  var params = merge({
    callback: callbackFn
  }, options.params)
  var query = serialize(params)
  var url = options.url
  url += ~url.indexOf('?') ? '&' : '?' + query

  script.onload = function () {
    delete window[callbackFn]
    document.head.removeChild(script)
  }
  script.onerror = function () {
    script.onload()
    options.faild && options.faild()
  }
  script.src = url
  window[callbackFn] = options.success
  document.head.appendChild(script)
}

Usage:

jsonp({
  url: 'https://xxx.com/newsDetail',
  params: {
    id: 1
  },
  success: function (res) {
    // success
  },
  faild: function () {
    // faild
  }
})