5.4. Language Enhancements
Mozilla's JavaScript language has a few features beyond ECMA-262 Edition 3.
5.4.1. Mozilla SpiderMonkey Enhancements
Mozilla's interpreter, SpiderMonkey, is relaxed about what constitutes a valid statement:
x++ % y++;
This is standards-compliant behavior but other JavaScript implementations do not support it.
Perhaps the most useful standards extension is a feature that allows JavaScript get and set methods to be attached to an object property. In other words, when the property is read or written to, a whole function runs as a side-effect. The function must implement the normal action that occurs when a property is read or written as well. Listing 5.6 illustrates these extensions at work.
Listing 5.6. Creating an ...
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