我发现xhr诡异的问题，自动重发请求，而且不会断。

我调用一登录接口，如果返回值status=401的场景下，会不断收到来自客户端的请求，这个问题100%发生。那位大侠可指点一下。通过console.log，xhr.send只执行了一次。

post: function(params) {  
        var xhr = new plus.net.XMLHttpRequest()  
        xhr.onreadystatechange = function() {  
            if (xhr.readyState === 4) {  
                if (xhr.status == 200) {  
                    return params.success(JSON.parse(xhr.responseText))  
                } else {  
                    return params.error(xhr.status, JSON.parse(xhr.responseText))  
                }  
            }  
        }  
        if(params.timeout){  
            xhr.timeout = params.timeout  
        }         
        xhr.open('POST', MiniUtil.createAPI(params.url))  
        xhr.setRequestHeader('Content-Type', 'application/json')  
        if (params.header) {  
            for (var key in params.header) {  
                xhr.setRequestHeader(key, params.header[key])  
            }  
        }   
                //通过console.log，这里只执行了一次。  
        xhr.send(JSON.stringify(params.data))  
    }

下面是服务器端日志信息

--> POST /api/v1/oauth2/token 401 11ms -  
  <-- POST /api/v1/oauth2/token  
111111  
{ name: 'a b c',  
  password: 'qqqqqqqq',  
  device_name: 'iOS',  
  client_id: 'Lt7hPcA6nuX38FY4',  
  client_secret: 'vV2RpBsZBE4pNGG2' }  

  OAuth2Error: Client credentials are invalid  
      at OAuth2Error (/home/data/demo.minicloud.io/node_modules/koa-oauth-server/node_modules/oauth2-server/lib/error.js:30:12)  
      at /home/data/demo.minicloud.io/node_modules/koa-oauth-server/node_modules/oauth2-server/lib/grant.js:147:19  
      at /home/data/demo.minicloud.io/lib/router/api/oauth2/model.js:68:24  
      at GeneratorFunctionPrototype.next (native)  
      at onFulfilled (/home/data/demo.minicloud.io/node_modules/co/index.js:64:19)  
      at process._tickCallback (node.js:353:9)  

  --> POST /api/v1/oauth2/token 401 8ms -  
  <-- POST /api/v1/oauth2/token  
111111  
{ name: 'a b c',  
  password: 'qqqqqqqq',  
  device_name: 'iOS',  
  client_id: 'Lt7hPcA6nuX38FY4',  
  client_secret: 'vV2RpBsZBE4pNGG2' }  

  OAuth2Error: Client credentials are invalid  
      at OAuth2Error (/home/data/demo.minicloud.io/node_modules/koa-oauth-server/node_modules/oauth2-server/lib/error.js:30:12)  
      at /home/data/demo.minicloud.io/node_modules/koa-oauth-server/node_modules/oauth2-server/lib/grant.js:147:19  
      at /home/data/demo.minicloud.io/lib/router/api/oauth2/model.js:68:24  
      at GeneratorFunctionPrototype.next (native)  
      at onFulfilled (/home/data/demo.minicloud.io/node_modules/co/index.js:64:19)  
      at process._tickCallback (node.js:353:9)