node监听80端口权限问题

报了这个错误：

　　Error: listen EACCES: permission denied 127.0.0.1:80

   　　 at Server.setupListenHandle [as _listen2] (net.js:1273:19)

　　    at listenInCluster (net.js:1338:12)

　　    at GetAddrInfoReqWrap.doListen [as callback] (net.js:1471:7)

   　　 at GetAddrInfoReqWrap.onlookup [as oncomplete] (dns.js:62:10)

　　Emitted 'error' event at:

   　　 at emitErrorNT (net.js:1317:8)

　　    at process._tickCallback (internal/process/next_tick.js:63:19)

在执行 node 1.js前加上sudo