Get the values of product from database in javascript

Can someone help please i have a code and want the quantity to be retrieved from the database and loaded to each textfield row.can someone help debug. thanks.

<SCRIPT LANGUAGE="JavaScript">
       function getValues(objName,objName2,objName3)

    {    

        var var3 = "";

        var arr = new Array();

        arr = document.getElementsByName(objName);

        arr2 = document.getElementsByName(objName2);

        arr3 = document.getElementsByName(objName3);

        for(var i = 0; i < arr.length; i++)

        {

            for(var i = 0; i < arr2.length; i++)

            {

            for(var i = 0; i < arr3.length; i++)

            {



                var obj1 = document.getElementsByName(objName2).item(i);

                var var2 = obj1.value;



                var obj = document.getElementsByName(objName).item(i);

                var var1 = obj.value;



                var obj3 = document.getElementsByName(objName3).item(i);

                var var3 = obj3.value;

                var var4 = var1 * var2;

                document.getElementsByName(objName3).item(i).value=var4;



            }        

            }

        }    



    }

    </script>


<table id="dataTable" width="597" border="0">
                    <tr>
                      <td width="20"><input name="s_no[]" readonly="readonly"  type="text" value="1" size="2"/></td>
                      <td width="114"><select name="product[]" id="product[]">
                        <option selected="selected">-- Select Product --</option>
                        <?php $sql1=mysql_query("SELECT * FROM products");
        while($fet=mysql_fetch_array($sql1)){
        $productname=$fet['productname'];
        //$uname=$fet['uname'];
        echo "<option value='$productname'> $productname </option>";

        }?>
                      </select></td>
                      <td width="144"><input name="qty[]" type="text" size="10"/></td>
                      <td width="144"><input  name="unitprice[]" type="text" onblur="getValues('qty[]','unitprice[]','amount[]')" onmouseout="getValues('qty[]','unitprice[]','amount[]')" size="10"/></td>
                      <td width="153"><input name="amount[]" type="text" onblur="getValues('qty[]','unitprice[]','amount[]')" onclick="getValues('qty[]','unitprice[]','amount[]')" size="15"/></td>
                    </tr>
                  </table>

                  <input type="button" value="Add Row" onclick="addRow('dataTable')" />
                  <input type="button" value="Delete Row" onclick="deleteRow('dataTable')" /></td>

              <tr>
                <td height="24"><input type="submit" name="submit" value="Submit" />
                  <input type="reset" name="Submit2" value="Cancel" /></td>
              </tr>