Change stylesheet of an answer option column in a single grid question

Challenge

In order to highlight an answer option column

As a questionnaire creator

I want to change the style sheet of a specific answer option column in a single grid question

Example

I have a single grid question like below.

I want to change the style of Don't know column.

Code

 1 //change style of a SINGLE grid question's answer option column
 2 //answerOptionValue: value of the answer option column
 3 //newColor: the new background color of the column's cells
 4 quest.changeAnswerOptionColumnStyle = function(answerOptionValue, cssClass)
 5 {
 6     //change style of answer option text
 7     $("#grid_answeroption_text_" + answerOptionValue).addClass(cssClass);
 8    
 9     //change style of answer option cells
10     $("input:radio").each(
11         function(i)
12         {
13             if ($(this).val() == answerOptionValue)
14                 $(this).parent().addClass(cssClass);
15         }
16     )
17 }
18 quest.onInit = function()
19 {
20 	//insert a cell before Don't know on header
21 	var dontKnow_value = 3;
22 		
23 	this.changeAnswerOptionColumnStyle(dontKnow_value, "another_column_css");
24 }