This works in Chrome but not IE, why?

Question

var shell = function (method) {
        window[method].apply(null, Array.prototype.slice.call(arguments, 1));
    };

shell('alert', 'monkey!');

See the answer to this question: http://stackoverflow.com/questions/120804/difference-between-array-slice-and-array-slice — Tim S. Van Haren, Jul 06 '10 at 12:45
@Jimmy this is not the case here. The standard doesn't insist this behavior. — gblazex, Jul 06 '10 at 12:53

gblazex · Accepted Answer · 2010-07-14T02:08:45.073

10

alert.apply is the problem. Alert is not part of the language, so it may not be even a function. It is implementation-dependent.

edited Jul 14 '10 at 02:08

answered Jul 06 '10 at 12:46

gblazex

4

Right - IE exposes APIs on `window` and on DOM elements to Javascript, but the exposure is limited and you generally cannot treat such things as if they were "real" Javascript components. – Pointy Jul 06 '10 at 12:48
Good point, but then shouldn't this work: var shell = function (method) { var fn = window[method]; fn.apply = Function.prototype.apply; fn.apply(null, Array.prototype.slice.call(arguments, 1)); }; shell('alert', 'monkey!'); – shawndumas Jul 06 '10 at 12:56
4

No. The problem is with the fact that `window` is a host object and `alert` is a property of a host object, and host objects are not obliged to behave like native objects. The following question is similar to yours: http://stackoverflow.com/questions/3060318/js-proxy-pattern-problem – Tim Down Jul 06 '10 at 13:13
Stupid IE. I gave up and used eval if the better way fails. – shawndumas Jul 06 '10 at 14:13

1 Answers1