xhr wrapper (modern browsers only)

xhr.js

/**
 * Make an XHR request accepts the following options
 *
 * method: (String) GET, POST, etc..
 * url: (String) http://...
 * async: (Boolean)
 * success: (Callback) fired on success (get xhr object)
 * error: (Callback) fired on error (get xhr object)
 * complete: (Callback) fired on both error and success (gets xhr object)
 * headers: (Object) list of headers
 * data: (Object) sent data
 *
 * @param {Object} options
 */
function request(options){
  var xhr = new XMLHttpRequest(),
      header;

  if(typeof(options) === 'undefined'){
    options = {};
  }

  function cb(type){
    if(options[type]){
      options[type](xhr);
    }
  }

  xhr.open(options.method || 'GET', options.url, options.async || true);

  xhr.onreadystatechange = function(){
    if(xhr.readyState === 4){
      if(xhr.status === 200){
        cb('success');
        cb('complete');
      } else {
        cb('error');
        cb('complete');
      }
    }
  };

  if(options.headers){
    for(header in options.headers){
      if(options.headers.hasOwnProperty(header)){
        xhr.setRequestHeader(header, options.headers[header]);
      }
    }
  }

  xhr.send(options.data || null);
}