jQuery Tablesorter order by td id not td values

Question

I have the next simple table and I use jQuery tablesorter for order by columns:

<table class="tablesorter" id="tableinvoices">
    <thead>
        <tr>
            <th>Name</th>
            <th>LastName</th>
            <th>Age</th>
        </tr>
    </thead>
    <tbody>
        <tr>
            <td><b id="n1">Sonia</b></td>
            <td><b id="l1">Soto</b></td>
            <td><b id="a1">20</b></td>
        </tr>
        <tr>
            <td><b id="n2">Carlos</b></td>
            <td><b id="l2">Rodriguez</b></td>
            <td><b id="a2">21</b></td>
        </tr>
        <tr>
            <td><b id="n3">Borja</td>
            <td><b id="l3">Valera</td>
            <td><b id="a3">21</td>
        </tr>
    </tbody>
</table>

If I click in Name, instead of order by values of td, order by id.

How do I order by the values​​?

Thanks for help and sorry for my bad english.

Answer 1

Here is a solution: http://jsfiddle.net/shtrih/Mh75v/

$(document).ready(function() { 
    // call the tablesorter plugin 
    $("table").tablesorter({ 
        // define a custom text extraction function 
        textExtraction: function(node) { 
            // extract data from id and return it 

            console.log(node.childNodes[0].innerHTML); // Make sure the output values
            return node.childNodes[0].innerHTML; 
        } 
    }); 
}); 

I've used this example: http://tablesorter.com/docs/example-option-text-extraction.html