/**
 * Remove and restore the defaultValue from a text input or textarea if it is unchanged.
 */
(function ($) {
    $.fn.defaultvalue = function () {
        var els = $(this).filter("textarea,input[type=text]");
        return els.each(function () {
            var el = $(this);
            var dv = el.attr("defaultValue");
            el.focus(function () {
                if (el.attr("value") == dv) {
                    el.attr("value", "")
                }
            }).blur(function () {
                if (el.attr("value") == "") {
                    el.attr("value", dv)
                }
            })
        })
    }
})(jQuery);

jquery.defaultvalue

jquery

JavaScript