如何使用node-horseman获取html时解决这个错误？

我使用模块node-horseman horseman从节点运行PhantomJS。 我想从githublogin页面获取html。 这是我的代码。

 var Horseman = require('node-horseman'); var horseman = new Horseman(); horseman .open('https://github.com/login') .html() .log() .close(); 

但是我得到错误。

 Unhandled rejection eval@[native code] evaluatePage global code evaluateJavaScript@[native code] evaluate@phantomjs://platform/webpage.js:390:39 phantomjs://code/bridge.js:121:61 at /Users/larry/Desktop/repos/getFollower/node_modules/node-horseman/lib/actions.js:989:36 at tryCatcher (/Users/larry/Desktop/repos/getFollower/node_modules/bluebird/js/release/util.js:16:23) at Function.Promise.fromNode.Promise.fromCallback (/Users/larry/Desktop/repos/getFollower/node_modules/bluebird/js/release/promise.js:178:30) at Horseman.<anonymous> (/Users/larry/Desktop/repos/getFollower/node_modules/node-horseman/lib/actions.js:987:29) at Horseman.tryCatcher (/Users/larry/Desktop/repos/getFollower/node_modules/bluebird/js/release/util.js:16:23) at Promise._settlePromiseFromHandler (/Users/larry/Desktop/repos/getFollower/node_modules/bluebird/js/release/promise.js:504:31) at Promise._settlePromise (/Users/larry/Desktop/repos/getFollower/node_modules/bluebird/js/release/promise.js:561:18) at Promise._settlePromiseCtx (/Users/larry/Desktop/repos/getFollower/node_modules/bluebird/js/release/promise.js:598:10) at Async._drainQueue (/Users/larry/Desktop/repos/getFollower/node_modules/bluebird/js/release/async.js:143:12) at Async._drainQueues (/Users/larry/Desktop/repos/getFollower/node_modules/bluebird/js/release/async.js:148:10) at Immediate.Async.drainQueues [as _onImmediate] (/Users/larry/Desktop/repos/getFollower/node_modules/bluebird/js/release/async.js:17:14) at tryOnImmediate (timers.js:543:15) at processImmediate [as _immediateCallback] (timers.js:523:5) 

我读了自述文件，但是我找不到错误在哪里。 我想可能还有其他一些问题。 有谁知道如何解决它？