Nodejs的npm安装模块时候报错：npm ERR! Error: CERT_UNTRUSTED的解决方法

npm http GET https://registry.npmjs.org/grunt-cli
npm http GET https://registry.npmjs.org/grunt-cli
npm http GET https://registry.npmjs.org/grunt-cli
npm ERR! Error: CERT_UNTRUSTED
npm ERR!     at SecurePair.<anonymous> (tls.js:1380:32)
npm ERR!     at SecurePair.emit (events.js:92:17)
npm ERR!     at SecurePair.maybeInitFinished (tls.js:979:10)
npm ERR!     at CleartextStream.read [as _read] (tls.js:471:13)
npm ERR!     at CleartextStream.Readable.read (_stream_readable.js:340:10)
npm ERR!     at EncryptedStream.write [as _write] (tls.js:368:25)
npm ERR!     at doWrite (_stream_writable.js:225:10)
npm ERR!     at writeOrBuffer (_stream_writable.js:215:5)
npm ERR!     at EncryptedStream.Writable.write (_stream_writable.js:182:11)
npm ERR!     at write (_stream_readable.js:601:24)
npm ERR! If you need help, you may report this log at:
npm ERR!     <http://github.com/isaacs/npm/issues>
npm ERR! or email it to:
npm ERR!     <npm-@googlegroups.com>

npm ERR! System Linux 2.6.32-220.13.1.el6.x86_64
npm ERR! command "node" "/usr/bin/npm" "install" "-g" "grunt-cli"
npm ERR! cwd /usr/local/src/elasticsearch-head-master
npm ERR! node -v v0.10.33
npm ERR! npm -v 1.3.6
npm ERR! 
npm ERR! Additional logging details can be found in:
npm ERR!     /usr/local/src/elasticsearch-head-master/npm-debug.log
npm ERR! not ok code 0

 解决

npm config set strict-ssl false

接下来继续执行安装命令解决