Finding column index using jQuery when table contains column-spanning cells

Question

Using jQuery, how can I find the column index of an arbitrary table cell in the example table below, such that cells spanning multiple columns have multiple indexes?

HTML

<table>
  <tbody>
    <tr>
      <td>One</td>
      <td>Two</td>
      <td id="example1">Three</td>
      <td>Four</td>
      <td>Five</td>
      <td>Six</td>
    </tr>
    <tr>
      <td colspan="2">One</td>
      <td colspan="2">Two</td>
      <td colspan="2" id="example2">Three</td>
    </tr>
    <tr>
      <td>One</td>
      <td>Two</td>
      <td>Three</td>
      <td>Four</td>
      <td>Five</td>
      <td>Six</td>
    </tr>
  </tbody>
</table>

jQuery

var cell = $("#example1");
var example1ColIndex = cell.parent("tr").children().index(cell);
// == 2. This is fine.

cell = $("#example2");
var example2ColumnIndex = cell.parent("tr").children().index(cell);
// == 2. It should be 4 (or 5, but I only need the lowest). How can I do this?

Answer 1

You could do something like this:

 var index = 0;
 cell.parent('tr').children().each( 
     function(idx,node) { 
           if ($(node).attr('colspan')) {
             index+=parseInt($(node).attr('colspan'),10); 
           } else {
              index++;
           }

         return !(node === cell[0]);
     }
 );
 console.log(index);

It'd probably make sense to do it as a plugin or via extend.

Answer 2

Here's a plugin which can calculate the 'noncolspan' index.

$(document).ready(
        function()
        {
        console.log($('#example2').getNonColSpanIndex()); //logs 4
        console.log($('#example1').getNonColSpanIndex()); //logs 2
    }

);

$.fn.getNonColSpanIndex = function() {
    if(! $(this).is('td') && ! $(this).is('th'))
        return -1;

    var allCells = this.parent('tr').children();
    var normalIndex = allCells.index(this);
    var nonColSpanIndex = 0;

    allCells.each(
        function(i, item)
        {
            if(i == normalIndex)
                return false;

            var colspan = $(this).attr('colspan');
            colspan = colspan ? parseInt(colspan) : 1;
            nonColSpanIndex += colspan;
        }
    );

    return nonColSpanIndex;
};

Answer 3

Mine is quite similar to SolutionYogi's, minus the creation of a plugin. It took me a bit longer... but I'm still proud of it so here it is :)

cell = $("#example2");
var example2ColumnIndex2 = 0;

cell.parent("tr").children().each(function () {
    if(cell.get(0) != this){
     var colIncrementor = $(this).attr("colspan");
     colIncrementor = colIncrementor ? colIncrementor : 1;
     example2ColumnIndex2 += parseInt(colIncrementor);
    }
});
console.log(example2ColumnIndex2);