function textCounter(field, countfield, maxlimit){
 if (field.value.length > maxlimit){
  field.value = field.value.substring(0, maxlimit);
  }
 else{ 
  countfield.value = maxlimit - field.value.length;
  }
}

function roll_over(img_name, img_src){
   document[img_name].src = img_src;
   }