Most browsers and implementations do allow a trailing comma, the big BUT is the
"Internet Explorer".
A trailing comma in most InternetExplorer versions causes BIG trouble. It'll throw wierd, crazy, strange and unreasonable errors .. you have no idea where you're at! This is terrible, you'll fall into deep and serious depressions. The disease also has a name, "evil comma of doom" it was called once.
Conclusion: NEVER.. ever! use a trailing comma in Javascript.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…