$("#right_div2 input[type='text'][class='textClass'][id^='asd_']").live("keydown",function(event) {

                var desValue = $(this).val()+event.char;

                if(event.keyCode>31 && event.keyCode != 128)

                {

                    if(!/(^(\d+)$)|(^(\d+\.)$)|(^(\d+\.[05])$)/.test(desValue))

                    {

                        event.preventDefault();

                    }

                }

            });