function fix_input_rule( element ) {
 
    var focus = function () {
        if ( element.value === '' ) {
            element.className = element.className.replace( / *background/, '' );
        }
        return true;
    };
    var blur = function () {
        if ( element.value === '' && !element.className.match(/ *background/ ) ) {
            element.className += ' background';
        }
        return true;
    };
    element.onfocus = focus;
    element.onblur = blur;
    element.onkeyup = focus;
}

var fix_rules = {

    '#gp_login': fix_input_rule,
    '#gp_pass' : fix_input_rule
};



Behaviour.register(fix_rules);