> Using these accessors, the VMs become able to do anything that JS can do.
In fact the source language is likely to be JS itself; a JS-to-some-sort-of-vm-bytecode-to-JS compiler is made. I know that Tencent has a similar VM; an interesting aspect of that VM is that the instruction set is dependent on the code being compiled (and the opcodes are dynamically generated and shuffled when compiling), so unused instructions are not generated.
Another reason to use `void 0` is that "void 0" takes only 6 characters while "undefined" takes 9, saving some bandwidth. It is common practice for JavaScript minifiers to use this substitution.
Microsoft (at least used to) require account passwords to not include the part before @ in email addresses. My email address was a@(domain).net, and therefore I was prevented from using any password including the letter "a".
The character 囍 means "double happiness" literally, and is often used in wedding ceremonies among other places here in China. It is also included in the Xinhua dictionary, the semi-official dictionary in mainland China.