java - How to get parameters of a table column in a servlet? -

good evening, how parameters of chk_group input inside servlet using request.getparametervalues here's jsp form:

    <form name="mainform" action="deleteservlet" method="get">     <table border=2 bordercolor=yellow width="120px" id="product_table">         <tr>             <td></td>             <td><b>carid</b></td>             <td><b>description</b></td>             <td><b>quantity</b></td>             <td><b>price</b></td>             <td><b>cc.no</b></td>             <td><b>engine</b></td>             <td><b>cylinder.no</b></td>             <td><b>maxspeed</b></td>             <td><b>petroltype</b></td>             <td><b>petrolcapacity</b></td>         </tr>         <c:foreach items="${product_list}" var="car">             <tr>                 <td><input type="checkbox" name="chk_group" /></td>                 <td><c:out value="${car.carid}" /></td>                 <td><c:out value="${car.cardesc}" /></td>                 <td><c:out value="${car.quantity}" /></td>                 <td><c:out value="${car.price}" /></td>                 <td><c:out value="${car.engincc}" /></td>                 <td><c:out value="${car.trans}" /></td>                 <td><c:out value="${car.noofcylinder}" /></td>                 <td><c:out value="${car.topspeed}" /></td>                 <td><c:out value="${car.fueltype}" /></td>                 <td><c:out value="${car.fuelcapacity}" /></td>             </tr>         </c:foreach>     </table>     </form> 

note:for each checkbox set value when checked value of corresponding carid value:

function setcheckboxvalue(tableid) {     try {          var table = document.getelementbyid(tableid);         var rowcount = table.rows.length;         ( var = 0; < rowcount; i++) {             var row = table.rows[i];              var chkbox = row.cells[0].childnodes[0];             if (null != chkbox && true == chkbox.checked) {                 var carid = table.rows[i].cells[1].innerhtml;                 table.rows[i].cells[0].value = carid;              }          }      } catch (e) {         alert(e);     } } 

you haven't specified checkbox value. when form submitted, end receiving empty string checked value. need give checkbox unique value can uniquely identify checked row. every other html input element, checkbox value becomes request parameter value.

e.g., car id:

<input type="checkbox" name="chk_group" value="${car.carid}" />