Cannot read property 'length' of undefined

Black Kasper

hello

i have a table the table that i have populate with php , it has 8 (columns) with the 8 (rows) , but it gives me the error on console it says "
Uncaught TypeError: Cannot read property 'length' of undefined
at Ka (jquery.dataTables.min.js:23)
at HTMLTableRowElement.<anonymous> (jquery.dataTables.min.js:16)
at jquery-1.12.4.js:142
at Function.map (jquery-1.12.4.js:484)
at jQuery.fn.init.map (jquery-1.12.4.js:141)
at oa (jquery.dataTables.min.js:16)
at e (jquery.dataTables.min.js:92)
at HTMLTableElement.<anonymous> (jquery.dataTables.min.js:93)
at Function.each (jquery-1.12.4.js:370)
at jQuery.fn.init.each (jquery-1.12.4.js:137)
"

what's the problem ?

kthorngren

My guess is the data returned from the server doesn't line up with the 8 columns defined. Its hard to say without seeing your code and the data. Do you get a pop up message with a link to a technote? If so, follow the steps to troubleshoot the issue.

It could be that something in your Datatables init code is referencing a column number outside of the column defined.

If not at least post a debug output:
https://datatables.net/manual/tech-notes/10

Kevin

Black Kasper

this is my debug output

http://debug.datatables.net/ocibuq

and this is my code

<table id="myTable" class="table table-fixed">

          <thead>
          <th>Student ID</th>
          <th>Student Name</th>
         
             
              <?php
              $countmodel=0;
              $JustForCountModule=0;
              $counter=5;
              $Count_Curves=0;
              $Total_Module_Mark=0;
              $Sum_Each_Module=0;
              $Select1 = mysqli_query($con,"SELECT grades.ModelID,model.modelname,model.modelcode from grades INNER JOIN student ON grades.StudentID = student.StudentID INNER JOIN model ON grades.ModelID = model.ModelID Where DepartmentName='".$dep."' group by modelid");
              while($Row = mysqli_fetch_array($Select1))
              {         
                $countmodel++;
                  $JustForCountModule++;
                echo "<th >".$Row["modelname"]."</th>";
                
                
              }
              // Get Total Mark Of Module 
              $Total_Module_Mark = 50 * $countmodel;
             
              $countmodel = $countmodel + 1;
              
              ?>
              <th>Needed Marks</th>
          </tr>
          </thead><tbody>
              <tr><?php
            $Select2 = mysqli_query($con,"SELECT student.StudentID,grades.Total1,student.StudentName,student.DepartmentID from grades INNER JOIN student ON grades.StudentID = student.StudentID INNER JOIN model ON grades.ModelID = model.modelid Where DepartmentID='".$depid."'");
              while($Row2 = mysqli_fetch_array($Select2))
              {
                
                $counter++;
                
                
                $Count_Curves++;
                if( $counter < $countmodel)
                {   
                    
                   if($Row2["Total1"] > 50)
                   {
                        
                        echo "<td>".$Row2["Total1"]."</td>";
                                        
                   }    
                   else
                   {
                        echo "<td style='background-color:#bfbfbf;color:white;color:black;'>".$Row2["Total1"]."</td>";
                            $Sum_Each_Module = $Sum_Each_Module + (50 - $Row2["Total1"]);
                   }
                 
                   
                   
                }
                
                else
                {
                    if( $Row2["Total1"] < 50)
                    {
                    echo "<tr></tr>";   
                    echo "<td>".$Row2["StudentID"]."</td>";
                    echo "<td>".$Row2["StudentName"]."</td>";
                    echo "<td style='background-color:#bfbfbf;'>".$Row2["Total1"]."</td>";
                    $Sum_Each_Module = $Sum_Each_Module + (50 - $Row2["Total1"]);
                    
                    }
                    else
                    {
                        echo "<tr></tr>";   
                        echo "<td>".$Row2["StudentID"]."</td>";
                        echo "<td>".$Row2["StudentName"]."</td>";
                        echo "<td>".$Row2["Total1"]."</td>";
                        
                    }
                    $counter=1;     
                    
                }
                if($counter == $JustForCountModule)
                   {
                       
                       if ($Sum_Each_Module > 1)
                       {
                       echo "<td  style='background-color:#e9ffd3;'>".$Sum_Each_Module."</td>";
                       $Sum_Each_Module=0;
                       }
                       else
                       {
                        echo "<td>".$Sum_Each_Module."</td>";
                       }
                                     
                 }
              } 
             
              ?>
              
              </tr>
              </tbody>
          </table>

and at the attachment i upload my above code output

Edited by Allan - Syntax highlighting. Details on how to highlight code using markdown can be found in this guide.

tangerine

Do you actually have a "dataSrc" called "rows"?

allan

There isn't actually an option called just dataSrc so that shouldn't make any difference. There is ajax.dataSrc, but Ajax doesn't appear to be used here.

@Black Kasper - Can you do a "view source" and send us the rendered HTML please?

Allan

Black Kasper

right i didn't retrieve data using ajax . i would be retrieve using ajax ?
please look at the attachment

tangerine

The attachment is not a "view source", which Allan asked for.

Black Kasper

@tangerine , view source means right click on the page and click on View Page Source ... right or wrong ?

tangerine

Right.

Black Kasper

so that's it bro . believe me

tangerine

No, it is not. It is the HTML page, not the page source, but it's probably usable anyway.

kthorngren

Looks like your HTML for the table is not quite right.

          <tbody>
              <tr>
              <tr></tr>
                <td>CS17001</td>
                <td>باخان عادل أحمد حمە</td>
                <td>57.3</td>
                <td style='background-color:#bfbfbf;color:white;color:black;'>38.4</td>
                <td style='background-color:#bfbfbf;color:white;color:black;'>50</td>
                <td>60.6</td>
                <td>69.75</td><td  style='background-color:#e9ffd3;'>11.6</td>
              <tr></tr>
...
              <tr></tr>
                <td>CS17094</td>
                <td>ئەوین ڕزگار  احمد سعید</td><td style='background-color:#bfbfbf;'>33.33</td>
                <td>59.6</td>
                <td>67</td>
                <td>57.6</td>
                <td>65.5</td><td  style='background-color:#e9ffd3;'>16.67</td>            

              </tr>

              </tbody>

Looks like you have an extra <tr> at the beginning followed by <tr></tr> which is followed by the row. The row should be between the <tr></tr>. And you have an extra </tr> at the end.

I think Datatables is looking between the <tr></tr> tags for the columns and is not finding anything.

Kevin