var count = 1;

     function add() {

         var tbl = document.all.ci;

         var rows = tbl.rows.length;

         var tr = tbl.insertRow(rows);

         var e_id = tr.insertCell(0);

         e_id.innerHTML = '<input type="text" name="e_id' + count + '" size="7"  />';

         var class_id = tr.insertCell(1);

         class_id.innerHTML = '';

         var memo = tr.insertCell(2);

         memo.innerHTML = '<input type="text" name="memo' + count + '" size="14" />';

         var del = tr.insertCell(3);

         del.innerHTML = '<input type="button" onclick="del(this)" value="删除" />';

         count++;

     }

     function del(btn) {

         var tr = btn.parentElement.parentElement;

         var tbl = tr.parentElement;

         if (tr.rowIndex >= 1) {

             tbl.deleteRow(tr.rowIndex);

         } else {

         }

     };