this.form.submit() not working

Question

    <form name="formUnbook" method="post" action='<%=response.encodeURL("dist-sales-order-edit.do")%>'>
                        <input type="hidden" name="formName"  value=<%=formName%>>
                        <input type="hidden" name="docTableItem" value="<%=docTableItem%>"> 
                        <input type="hidden" name="docKeyItem" value="<%=docKeyItem%>"> 
                        <%eventCalendarLinkName  = "UnBook";%>
<a class="smalllink4" href="#" onClick="fnUnbook();"><%=eventCalendarLinkName%></a>
</form>
......................................................................................
<script language="JavaScript">
        function fnUnbook(){
            answer = confirm('<%=bundle.getString("label_areYouSure")%>');
            if(answer)
            {
                this.form.submit();
            }
        }
    </script>

This.form.submit(); doesn't submit the form. Any suggestion? I also tried document.form.submit(); but doesn't worked. Where is the problem?

Answer 1

change this.form.submit(); to document.getElementsByName("formUnbook")[0].submit();

Answer 2

Try modifying your code like that (add id to the form):

<form name="formUnbook" id="formUnbook" method="post" action='<%=response.encodeURL("dist-sales-order-edit.do")%>'>
<!-- other stuff here -->

<script type="text/javascript">
function fnUnbook() {
  if( confirm('<%=bundle.getString("label_areYouSure")%>') ) {
    return document.getElementById('formUnbook').submit();
  }
}
</script>