$.fn.rangeSelect = function() {
    var lastCheckbox = null;
    var $spec = this;

    $spec.bind("click", function(e) {
        if (lastCheckbox != null && e.shiftKey) {
            $spec.slice(
                Math.min($spec.index(lastCheckbox), $spec.index(e.target)),
                Math.max($spec.index(lastCheckbox), $spec.index(e.target)) + 1
            ).attr({checked: e.target.checked ? "checked" : ""});
        }
        lastCheckbox = e.target;
    });
    return $spec;
 };