What is wrong with this javascript with jsp - asap help needed

Question

<script language="javascript">
function checkSubmit(form){
                // Loop from zero to the one minus the number of radio button selections
                for (counter=0; counter < document.submitform.authortitle.length; counter++){
                    if (form.authortitle[counter].checked){
                        var splitStr = document.submitform.authortitle[counter].value;
                        alert(splitStr);
                        var splitStrArray = new Array();
                        splitStrArray = splitStr.split(","); alert(splitStrArray[2]);
                        splitStrArray[2].trim();
                        if(splitStrArray[2].equals("null")){
                            alert("true");
                            //replace the form action with somefile.jsp
                            document.forms[0].action="searchAmazon.jsp";
                            form.submit();
                        }else{
                            document.forms[0].action="isbnSearch.jsp";
                            form.submit();     
        </script>the above javascript method is acting stupid.. it shows the first two alerts but does not go in the if statement "if(splitStrArray[2].equals("null")){ " and does not show the third alert. i do not c any problems pls help... when i click the option and submit it gives me a jasper exception pointing to some line which does not involve this code...

Answer 1

it has started working now basically the problem was the trim() method which i have removed and have changed .equals("null") to == ..
BUT NOW it always does the else command and goes to the isbnsearch page even if the value is null (if null then it should go to another page)...