How to prevent multiple shortcut events for JQuery Hotkeys plugin

$(document).bind('keydown', 'ctrl+s', function (e) {
         DoSomethings();
        e.preventDefault();
    });

preventDefault method in javascirpt

event.preventDefault();

Cancels the event if it is cancelable, without stopping further propagation of the event.
Reference: https://developer.mozilla.org/en/DOM/event.preventDefault