jQuery.fn.css »

jQuery.fn.css = function( name, value ) {
    // Setting 'undefined' is a no-op
    if ( arguments.length === 2 && value === undefined ) {
        return this;
    }
 
    return jQuery.access( this, name, value, true, function( elem, name, value ) {
        return value !== undefined ?
            jQuery.style( elem, name, value ) :
            jQuery.css( elem, name );
    });
};