function _jSubmit(){
       var jmail = document.getElementById('email_address');
	   if(jmail.value=="" || jmail.value=='Enter your email address'){
			  alert('please enter your email address');return false;   
	    }else{
	        if(jmail.value.indexOf('@')==-1 ||jmail.value.indexOf('.')==-1){
               alert("please enter valid email address e.g. you@nparks.gov.sg");return false;
		    }
	   } self.location='http://www.nparks.gov.sg/cms/index.php?option=com_chronocontact&chronoformname=mailing_list&Itemid=48&email=' + jmail.value;  return false;
  }