jquery监控input输入框的变化

(function($) {
    $.fn.watch = function(callback) {
        return this.each(function() {
            //缓存以前的值
            $.data(this, ‘originVal‘, $(this).val());

            //event
            $(this).on(‘keyup paste‘, function() {
                var originVal = $(this, ‘originVal‘);
                var currentVal = $(this).val();

                if (originVal !== currentVal) {
                    $.data(this, ‘originVal‘, $(this).val());
                    callback(currentVal);
                }
            });
        });
    }
})(jQuery);

$(document).ready(function() {
    $("#barcode").watch(function(value) {  
        //...
    } 
    }); 
});