Disable preventing shortcuts and some mouse events by e.preventDefault()

Question

I'm using contenteditable on my website (and JS/JQuery). I have a limit (maxlength) of 160 letters in it. When it comes to 160, function addOnTypeKeyDown() fires (when typing) e.preventDefault(), but this function prevent Ctrl+C, prevent mouse selection, prevent Ctrl+A as long as I click backspace (so e.preventDefault() isn't working).

My question is how can I "switch on" options like above (Ctrl+C and so on...) without letting user type letters.

I know that I can use input or textarea, but I'm asking how can I solve this problem using contenteditable?

I used e.which for Ctrl+C and mouse events, but that didn't work.

Function looks like that:

function addOnTypeKeyDown(event){
    var cntMaxLength = parseInt($(this).attr('maxlength'));

    event = event || window.event;

    if ($(this).text().length >= cntMaxLength) {
        if(!(event.which==8))
        {
            event.preventDefault();
            $(this).parent().find("#error").css("display", "block");
        }
    }
    else{
        $(this).parent().find("#error").css("display", "none");
    }
}

Thanks for your time and effort.