function roundCorners(id){

  			var left = document.getElementById(id+'_l');  			
  			var isActive = document.getElementById(id).className;
  			
  			if(isActive!='active_item') {
  			
  	  		if(left.className=='corner_l') {
  				left.className='corner_l_on';  				
  	  		} else {
  	  			left.className='corner_l';
  	  		}

  	  		var right = document.getElementById(id+'_r');
  	  		if(right.className=='corner_r') {
  	  			right.className='corner_r_on';
	  		} else {
	  			right.className='corner_r';
	  		}
  	  		
  			}
 			  			
}