//uncomment to prevent on startup
//removeDefaultFunction();
/** Prevents the default function such as the help pop-up **/
function removeDefaultFunction()
{
    window.onhelp = function () { return false; }
}
/** use keydown event and trap only the F-key,
 but not combinations with SHIFT/CTRL/ALT **/
$(window).bind('keydown', function(e) {
    //This is the F1 key code, but NOT with SHIFT/CTRL/ALT
    var keyCode = e.keyCode || e.which;
    if((keyCode == 112 || e.key == 'F1') &&
            !(event.altKey ||event.ctrlKey || event.shiftKey || event.metaKey))
    {
        // prevent code starts here:
        removeDefaultFunction();
        e.cancelable = true;
        e.stopPropagation();
        e.preventDefault();
        e.returnValue = false;
        // Open help window here instead of alert
        alert('F1 Help key opened, ' + keyCode);
    }
    // Add other F-keys here:
    else if((keyCode == 113 || e.key == 'F2') &&
            !(event.altKey ||event.ctrlKey || event.shiftKey || event.metaKey))
    {
        // prevent code starts here:
        removeDefaultFunction();
        e.cancelable = true;
        e.stopPropagation();
        e.preventDefault();
        e.returnValue = false;
        // Do something else for F2
        alert('F2 key opened, ' + keyCode);
    }
});