原生ajax()函数封装
  • @param {string}opt.type http连接的方式,包括POST和GET两种方式
    • @param {string}opt.url 发送请求的url
    • @param {boolean}opt.async 是否为异步请求,true为异步的,false为同步的
    • @param {object}opt.data 发送的参数,格式为对象类型
    • @param {function}opt.success ajax发送并接收成功调用的回调函数
function ajax(opt) {
  opt = opt || {};
  opt.method = opt.method.toUpperCase() || 'POST';
  opt.url = opt.url || '';
  opt.async = opt.async || true;
  opt.data = opt.data || null;
  opt.success = opt.success || function() {};
  var xmlHttp = null;
  if (XMLHttpRequest) {
    xmlHttp = new XMLHttpRequest();
  } else {
    xmlHttp = new ActiveXObject('Microsoft.XMLHTTP');
  };
  var params = [];
  for (var key in opt.data) {
    params.push(key + '=' + opt.data[key]);
  }
  var postData = params.join('&');
  if (opt.method.toUpperCase() === 'POST') {
    xmlHttp.open(opt.method, opt.url, opt.async);
    xmlHttp.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded;charset=utf-8');
    xmlHttp.send(postData);
  } else if (opt.method.toUpperCase() === 'GET') {
    xmlHttp.open(opt.method, opt.url + '?' + postData, opt.async);
    xmlHttp.send(null);
  }
  xmlHttp.onreadystatechange = function() {
    if (xmlHttp.readyState == 4 && xmlHttp.status == 200) {
      opt.success(xmlHttp.responseText);
    }
  };
}
JSRUN notes