Obfuscate variable and function names with junk words. On Windows, Jasob was easily the best http://www.jasob.com/ for it (I tried using many others including online offerings). You need to do this if worried about others seeing and using your code, especially competitors.

edit: am I stupid? But when you obfuscate, you also radically shorten the length of a JS file, thus making it quicker to download: EG:

function c(g){var m=0;while(m<g.length){var r=g[m];r.l=d(r.n,r.o);if(r.j==true){ r.k=e(r.n,r.o,r.l);}else{r.k=0;}r.t=f(r.l+r.k);m++;}}