Your environment has been set up for using Node.js 4.4.3 (ia32) and npm. C:\Documents and Settings\Administrator>npm install -g browser-sync npm ERR! Windows_NT 5.1.2600 npm ERR! argv "C:\Program Files\nodejs\node.exe" "C:\Program Files\nodejs\ node_modules\npm\bin\npm-cli.js" "install" "-g" "browser-sync" npm ERR! node v4.4.3 npm ERR! npm v2.15.1 npm ERR! code UNABLE_TO_VERIFY_LEAF_SIGNATURE npm ERR! unable to verify the first certificate npm ERR! npm ERR! If you need help, you may report this error at: npm ERR! <https://github.com/npm/npm/issues> npm ERR! Please include the following file with any support request: npm ERR! C:\Documents and Settings\Administrator\npm-debug.log C:\Documents and Settings\Administrator> 求助