michael@0: function tryItOut(code) {
michael@0:     f = eval("(function(){" + code + "})")
michael@0:     try {
michael@0:         f()
michael@0:     } catch (e) {}
michael@0: }
michael@0: tryItOut("x=7");
michael@0: tryItOut("\"use strict\";for(d in[x=arguments]){}");
michael@0: tryItOut("for(v in((Object.seal)(x)));x.length=Function")