I have one registration page in app, If any registration happen means I need to save the username and password in xml file. On Each registration registerInfo.xml is updated with extra <person></person> .How can I do that, Let's say My XML is as follows,
registerInfo.xml:
<?xml version="1.0" encoding="UTF-8"?>
<registerInfo>
<Person Usrname="vinod" Pswd="chawla" ></Person>
<!-- If any registration happen need to create on person tag iwth username and password attribute--> 
</registerInfo> 
HTML:
<!DOCTYPE html>
<html>
  <head></head>
<body>
 Username: <input name="" id="username" value=""  type="text" data-mini="true"><br>
 Password: <input name="" id="password" value=""  type="password" data-mini="true"><br>
 <input id="btnDefaultSMS" type="submit" value="Register" data-mini="false">
</body>
</html>