Javascript function work on all page except textareas, text boxes
===

My function (which is shown below) dedicated for "copy-protecting" page.(actually it's only visual thing. Advanced user can get from source code.) What I want to do get this function work on all page parts except textareas, textboxes. How can I achieve this result?

    (function($){
    
        $.fn.ctrl = function(key, callback) {
            if(typeof key != 'object') key = [key];
            callback = callback || function(){
                return false;
            }
            return $(this).keydown(function(e) {
                var ret = true;
                $.each(key,function(i,k){
                    if(e.keyCode == k.toUpperCase().charCodeAt(0) && e.ctrlKey) {
                        ret = callback(e);
                    }
                });
                return ret;
            });
        };
    
    
        $.fn.disableSelection = function() {
            $(window).ctrl(['a','s','c']);
            return this.each(function() {           
                $(this).attr('unselectable', 'on')
                .css({
                    '-moz-user-select':'none',
                    '-o-user-select':'none',
                    '-khtml-user-select':'none',
                    '-webkit-user-select':'none',
                    '-ms-user-select':'none',
                    'user-select':'none'
                })
                .each(function() {
                    $(this).attr('unselectable','on')
                    .bind('selectstart',function(){
                        return false;
                    });
                });
            });
        }
    })(jQuery);

