gistfile1.js

function array_diff(foo, bar) {
    var d=[], i=0, j=0;
    foo.sort();
    bar.sort();
    while (i < foo.length && j < bar.length) {
        var l = foo[i], r = bar[j];
        if (l < r) {
            d.push(l);
            i++;
        } else if (l == r) {
            i++;
            j++;
        } else {
            d.push(r);
            j++;
        }
    }
    while (i < foo.length) d.push(foo[i++]);
    while (j < bar.length) d.push(bar[j++]);
    return d;
}