Even if client that run your code (Desktop Browser, Mobile Browser, Smart TV..) have different memory availability, different bandwidth and different performances, it is always a good idea to develop code tailored to the clients with fewer resources. It is a matter of fact that lightweight code runs faster.
Google suggests an endless list of tools, however, I can tell you by experience, they are almost always very hard to get running, not very useful, and there’s always the risk of breaking code integrity by renaming variables and/or functions, inc cases where code execution depends on specific names.
You can skip previuos link if you want to perform a test, you can run the same piece of code that I use to minimize the livebox.js code:
cat ../logic/*.js ../LiveBox.js | “C:/Program Files (x86)/Microsoft/Microsoft Ajax Minifier/AjaxMin.exe” -js -out LiveBoxMinified.js –clobber