Replace nav string concatenation with join().
Replace nav string concatenation with join().

According to a Google JS optimization guide, join() is better than doing
+= to a running string when it is passing through a loop or
conditional statement.

Reference:
https://developers.google.com/speed/articles/optimizing-javascript

filipesilva/filipesilva.github.io,overcloudnine/cms.js,overcloudnine/cms.js,pezzell/pezzell,cdmedia/cms.js,epix360/cms.js,gnoejuan/cms.js,gnoejuan/cms.js,daz4126/daz4126.github.io,filipesilva/filipesilva.github.io,pezzell/pezzell,jhliberty/jhbtm,cdmedia/cms.js,daz4126/daz4126.github.io,jhliberty/jhbtm,epix360/cms.js