To install Wide, type:
go get -u -v github.com/88250/ide_stub
go get -u -v github.com/nsf/gocode
go get -u -v github.com/b3log/wide
To start the program, type:
cd $GOPATH/src/github.com/b3log/wide/
wide
Then visit using your browser on http://your_ip_address:7070
There are some other web-based IDE such as GoDev (lags when showing godoc), LimeText, Carpo, Atom (aur/atom-editor-bin), Brackets.io, and Conception-go (this one not a web-based :3 it's OpenGL)
Btw, I make a list on GoogleDocs to list all Go IDEs, you can contribute/edit it if you want..