```
> a = ["key","value"]
["key", "value"]
> o = {a[0]:a[1]}
SyntaxError: Unexpected token [

```

But this is OK

```
> o = {}
Object {}
> o[a[0]] = a[1];
"value"
> o
Object {key: "value"}

```

browser version: Chrome 37.0.2062.124 m

**Why** Syntax error ?
Dose here introduce a new context ? I don't familiar the ECMA spec.