<input value="1" type="radio" name="myradio" checked="checked"/>A
<input value="2" type="radio" name="myradio"  />B
<input value="3" type="radio" name="myradio" />C

<form action="#" name="test"> <input value="1" type="radio" name="myradio1" />A
<input value="2" type="radio" name="myradio2"  />B
<input value="3" type="radio" name="myradio3" />C
<input type='button' name='submit' value="Submit" class='submitBtn' onClick="validate(this.form)"> </form> <script type="text/javascript">
	function validate(nForm){
		
		var flag = false;
		for (i=0; i<nForm.length; i++)
		{
			
			if(nForm[i].type == 'radio') {
				if(nForm[i].checked == true) {
					flag = true;
				}
			}
		}
		
		if (!flag)
		{
			alert('Please complete all fields');
			return false;
		}
	}
</script>

<form action="#" name="test"> <input id="" name="answer[0]" type="radio" value="1" /> A
<input id="" name="answer[0]" type="radio" value="1" /> A
<input id="" name="answer[0]" type="radio" value="1" /> A

<br /> <input id="" name="answer[1]" type="radio" value="1" /> A
<input id="" name="answer[1]" type="radio" value="1" /> A
<input id="" name="answer[1]" type="radio" value="1" /> A

<input type='button' name='submit' value="Submit" class='submitBtn' onClick="validate(this.form)"> </form> <script type="text/javascript">
	function validate(nForm){
		
		var flag = false;
		var answer = [];
		
		
		for (i=0; i<nForm.length; i++)
		{
			
			if(nForm[i].type == 'radio') {
				if(!eval(nForm[i].name))
					eval(nForm[i].name+' = [];')
				eval(nForm[i].name+'.push('+nForm[i].checked+')')
			}
		}
		
		for(i =0; i<answer.length; i++) {
			flag = false;
			for(j = 0; j<3; j++) {
				if(answer[i][j] == true) {
					flag = true;
				}
			}
			if (!flag)
			{
				alert('Please complete all fields');
				return false;
			}
		}
	}
</script>