Remembering selected items on server round trip

Question

I am using GeoServer, GeoExt, PostGIS, etc (all the standard stuff).

I have a map displayed in my browser and performing a box select adds relevant items to my selection vector layer. In addition to this a popup box appears with a summary of selected items and against each layer summary is a hyperlink which when clicked causes a server round trip (this round trip is necessary as it displays the main detail of each selected item). The server round trip results in the map being re-displayed but now my selected items are no longer selected.

Can I maintain the list of selected items and keep them highlighted after the map re-draw?

I could probably cobble something together using cookies but was wondering if there is an easier solution!

Answer 1

Use HTML5 Web Storage, it is perfect for this purpose.

Web Storage is a method of storing data to a permanent store in the browser and does away with any need for Cookies.

There are two types of Storage

localStorage - stores data with no expiration date
sessionStorage - stores data for one session

This means that you could actually store you list across browser sessions if you wanted to by using the localStorage, or just for that web Session.

It is as easy as setting variables in JScript:

localStorage.mylist_1="ListContent"

then to retrieve use

var a = localStorage.mylist_1

Some excellent information and examples can be seen Here!

Answer 2

To complete Mark C answer and to give you an alternative to HTML5 option, I would say you can just use global javascript var to store your selected values.

It's not clear whether you currently refresh the full webpage or just the map. Anyway, just the map has to be refreshed. So you could just refresh the map container div using ajax and transmit your selected values with the ajax request using data options (from ajax jQuery method).

Here, you will find a small example on how to update the container : http://www.w3schools.com/jquery/tryit.asp?filename=tryjquery_ajax_ajax

And here, an example on how data options works.