How to Valid Radio Button Using JavaScript

My Facebook Profile
<html>
<head>
<script LANGUAGE="JavaScript">
function shakeel(form)
{

if ( ( form.gender[0].checked == false ) && ( form.gender[1].checked == false ) )
{
alert ( "Please choose your Gender: Male or Female" );
return false;
}


}
</script>
</head>
<body>
<form name="feedback" action="" method=post>
Your Gender:
<input type="radio" name="gender" value="Male"> Male
<input type="radio" name="gender" value="Female"> Female

<input type="button" name="SubmitButton" value="Submit" onClick="shakeel(this.form)">
<input type="reset" value="Reset">
</form>
</body>
</html>