Hidden Form field in Session handling

One of the major disadvantage with the URL Rewriting is that passing session data with the URL makes visible to every one who are requesting for the resource. To over come this problem the concept of hidden form field is introduced so that all the required session data can be able to pass to the requested resource without viewing to the user. Hidden field is one of the form element which is used to pass value keeping information abstract to the user. Hidden forms are not visible to the browser but it keeps the information secretly and can able to get the session data from the form fields using method getParameter(String).

Syntax of hidden form field :

<input type="hidden" name="sessioninfo" value="xxx"/>

We are getting the information present in the hidden text field by passing the string used in the name attribute i.e sessioninfo here to the getParameter(String).

Advantages with Hidden form field

1. It is possible with both POST and GET method type.
2. Information is not visible to the end user.

Disadvantages with Hidden form fields

1. Limited to the JSP ( supporting HTML form elements ), cannot be used with the servlet.

2. It is used in place of passing session data openly with the URL with the form submission .

3. Session tracking mechanism is not always possible only with the hidden form field. Somewhere hyperlinks are required which again follow the URL rewriting approach.

Note: It does not support full session tracking mechanism, but advantageous over URL rewriting.