No matter how complex you make your code, it can always be read, if necessary with abstract interpretation, i.e. automatically capturing the essence of your code. Code without knowledge of internals, variable names (I assume you’re already using minimization, for example with the YUI compressor), documentation, support, and generalization is worthless for anyone else.
If a competitor (or potential customers) of yours is stealing your code, consider simply suing them. If it’s some random guy on the internet, why do you care?
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solved How to secure javascript code from being run on other domain (stolen) ? need more ideas