Hi..guys! I have a function here to validate null selection of drop down menu and radio button.However,it seems like alert box couldn't be stopped display even though both fileds were already selected.Thanks for your generious help

Code:
<script language="JavaScript" type="text/JavaScript">
function nullValidation() {
    var x=document.getElementById("movieList");
    for (var i=0;i<x.length;i++)
    {
      if(x.elements[i].checked=="" || x.elements[i].selectedIndex == 0) 
      {
        alert("Please select "+x.elements[i].title+".");
        x.elements[i].focus();
        return false;
      }
    
    }
return true;
}
</script>
Code:
<form action="" method="post" name="movieList" 
onSubmit="return nullValidation();">