Why doesn't indexOf work on an array IE8?

Question

The below function works fine on Opera, Firefox and Chrome. However, in IE8 it fails on the if ( allowed.indexOf(ext[1]) == -1) part.

Does anyone know w

Answer 1

If you're using jQuery and want to keep using indexOf without worrying about compatibility issues, you can do this :

if (!Array.prototype.indexOf) {
    Array.prototype.indexOf = function(val) {
        return jQuery.inArray(val, this);
    };
}

This is helpful when you want to keep using indexOf but provide a fallback when it's not available.