Sort HTML table with a row header (2 row sort)

Table

ID	NAME	Value	SPECIALIZATION
Row Header 1			1
1	Angelina	-1	Computer Science
Row Header 2			2
2	Martina	10	Mathematics
Row Header 3			3
3	Tina	0.5	English
Row Header 4			4
4	Simran	100	Biology
Row Header 5			5
5	Christina	-99	Psychology

The code below allows the above table to sort the data values while keeping the row headers above. Something i couldn't find an example for on Google.

 function doSort(column, tableID, direction) {  
   var data = []  
   var table = document.getElementById(tableID);  
   var skip = 1; // skip column headers  
   // set up sortable data array [ sorted key, row data, header data ]  
   for (var i = skip + 1, l = table.rows.length; i < l; i=i+2) {  
           // grab each row - so we can clone later  
     var header_cell_row = table.rows[i - 1]; // header cell row data  
     var data_row = table.rows[i]; // sortable row data  
            var cell_data = table.rows[i].cells[column].innerHTML; // this is the bit we sort.  
             data.push([parseFloat(cell_data), data_row, header_cell_row])  
   };  
   //sort that array in the direction we ask  
   data.sort(  
     direction==0 ?  
       function(a,b){return a[0]<b[0]?-1:a[0]>b[0]?1:0} // ASC  
     :  
       function (a, b) { return a[0] > b[0] ? -1 : a[0] < b[0] ? 1 : 0} // DESC  
   )  
   // run thru sorted array  
   for (var i = 0, l = data.length; i < l; i++) {  
           // we append at the bottom of the original table the new sorted table  
           // as we have saved the real rows we can clone and append  
     //  
     // header row  
     //  
     var source = data[i][2];  
            table.appendChild(source.cloneNode(true));  
     //  
     // data row  
     //  
     var source = data[i][1];  
            table.appendChild(source.cloneNode(true));  
           //  
           // delete an old row from the table  
           //  
          table.deleteRow(1);  
           table.deleteRow(1);  
   }  
 }