Preserve page state for revisiting using browser back button

Question

I have a page that dynamically loads content based on a user pushing a button:

${document).ready(function)
{
    $("#myButton").click(function()
    {
        $("#dynamicDiv").load("www.example.com");
    });
}

The dynamic content works fine, I can fetch pages all day long. But after you follow a link to another page, then press the browser back button to come back to the page, the page is completely reset as though no dynamic content had ever been loaded.

I swear I've seen different behavior before, but maybe I'm insane. Shouldn't the browser preserve the state of the page, rather than re-rendering it?

EDIT: By the way, I'm using Play! framework, if that has any bearing on this.

Answer 1

The browser loads the page as it was first received. Any DOM modifications done via javascript will not be preserved.

If you want to preserve the modifications you will have to do some extra work. After you modify the DOM, update the url hash with an identifier that you can later parse and recreate the modification. Whenever the page is loaded you need to check for the presence of a hash and do the DOM modifications based on the identifier.

For example if you are displaying user information dynamically. Every time you display one you would change the url hash to something like this: "#/user/john". Whenever the page loads you need to check if the hash exists (window.location.hash), parse it, and load the user information.

Answer 2

Implementing browser back functionality is hard. It gets easier when you use a plugin like jquery.history.js.

http://tkyk.github.com/jquery-history-plugin/

Answer 3

epignosisx and Malcolm are both right. It's also known as "deep linking". We used the JQuery Address Plugin to deal with this in a recent Play application.

http://www.asual.com/jquery/address/

Answer 4

A technique I use for this is to serialize state to JSON, store it in the hash string, and then read it back when the page is navigated back to. This has been tested in IE10+, Firefox, Chrome.

Example:

// On state change or at least before navigating away from the page, serialize and encode the state
// data you want to retain into the hash string

window.location.hash = encodeURIComponent(JSON.stringify(myData));

// If navigating away using Javascript, be sure to use window.location.href over window.location.replace

window.location.href = '/another-page-url'

....

// On page load (e.g. in an init function), if there is data in the #hash, overwrite initial state data
// by decoding and parsing the JSON string

if (window.location.hash) {

    // Read the hash string omitting the # prefix

    var hashJson = window.location.hash.substring(1);

    // Restore the deserialized data to memory

    myData = JSON.parse(decodeURIComponent(hashJson));
}