Problem when to iterate through Radio Buttons

[goodamr]

Dear All,

I'm building an Question/Answer Application in which I generate the Questions and Answers from Oracle database.

I'd like to validate through javascript that the user should answer each question.

First, I iterate through the questions.
Then, inside each question, I check if the user has chosen an answer (If the radio button is checked). If not alert a message.

I get the answer through:

var ans_rdo = document.getElementsByName('answer'+i);

but, when I iterate through it to check if it's checked or not:

if(ans_rdo[j].checked == true)

I get this error:
Error: 'checked' is null or not an object

Here is the complete function:
------------------

function ValidateEntery() 
{
	var qst_cnt = Number(document.Form1.quest_count.value);//Number of Questions
	
	for(i=1; i <= qst_cnt; i++)
	{
		var chk_cnt = 0;//number of radio checked
		var ans_rdo = document.getElementsByName('answer'+i); //get the anser radio button
		for(j=1; j <= ans_rdo.length; j++)
		{
			[B][U]if(ans_rdo[j].checked == true)[/U][/B] // here I get this error: 'checked' is null or not an object
			{
				chk_cnt ++;
			}
		}
		
		if(chk_cnt <= 0)
		{
			alert("Please answer all questions");
			return false;
		}
		
	}		
}

--------------------------

[Dormilich]

the error implies that the fetched object is not a radio button (or checkbox). there might be another form element with that name.

[goodamr]

Thank you Dormilich for replying.

You are correct but the problem is because I have iterated through the radio buttons from 1:

for(j=1; j <= ans_rdo.length; j++)

I should begin the iteration from 0 like that:

for(j=0; j < ans_rdo.length; j++)

So the prblem has been solved.