跨浏览器的CORS

 function createCORSRequest(method, url){
      var xhr = new XMLHttpRequest();

      if("withCredentials" in xhr){
          xhr.open(method, url, true);
      }else if(typeof XDomainRequest != "undefined"){
          xhr = new XDomainRequest();
          xhr.open(method, url);
      }else{
          xhr = null;
      }

      return xhr;
 }

 var request = createCORSRequest("get", "http://www.somewhere-else.com/page/");

 if(request){
     request.onload = function(){
          //对request.responseText 进行处理
     }

     request.send();
 }