add a + symbol to the

I am using the following function to expand and collaplse the grids on my ASP.NET page. I want to add one more feature to show a + sign when the grids are collapsed and a minus sign when the grids are expanded. Could you please suggest what needs to be done please. <script type='text/javascript'> $(function(){ //When your page loads - initially hide all of the grid containers $('.grid-container').hide(); //When one of your grid-panel areas is clicked (but not the grid itself) $(".grid-panel").click(function(e){ //The grid-panel (and not the grid was selected) if($(e.target).closest('div').hasClass('grid-panel')){ //Toggle the appearance of the grid container $(this).find('.grid-container').toggle(); } }); }); </script>