js detect architecture

function get_bits_system_architecture() {
    var _to_check = [];

    if (window.navigator.cpuClass) {
        _to_check.push((window.navigator.cpuClass + '').toLowerCase());
    }

    if (window.navigator.platform) {
        _to_check.push((window.navigator.platform + '').toLowerCase());
    }

    if (navigator.userAgent) {
        _to_check.push((navigator.userAgent + '').toLowerCase());
    }

    var _64bits_signatures = [
        'x86_64',
        'x86-64',
        'Win64',
        'x64;',
        'amd64',
        'AMD64',
        'WOW64',
        'x64_64',
        'ia64',
        'sparc64',
        'ppc64',
        'IRIX64'
    ];
    var _bits = 32;

    outer_loop:
        for (var _c = 0; _c < _to_check.length; _c++) {
            for (var _i = 0; _i < _64bits_signatures.length; _i++) {
                if (_to_check[_c].indexOf(_64bits_signatures[_i].toLowerCase()) !== -1) {
                    _bits = 64;
                    break outer_loop;
                }
            }
        }

    return _bits;
}

function is_32bits_architecture() {
    return (get_bits_system_architecture() === 32);
}

function is_64bits_architecture() {
    return (get_bits_system_architecture() === 64);
}