I thought is was worth mentioning, that the Google Closure Libary has quite an interesting approach to this. They use the Closure compiler to handle it. First o

I thought is was worth mentioning, that the Google Closure Libary has quite an interesting approach to this. They use the Closure compiler to handle it. First of all only the pieces of code that are actually used are compiled into the final javascript file. You can also set compile flags in case you only want to target specific browsers, like mobile webkit, which will reduce code size even further.