用户在JavaScript中离开之前的HTML页面后会怎样？

Question

Assumes I have two HTML pages, let call them page1.html and page2.html. And then users navigate from page1.html to page2.html by made a call to assign or replace method of location object. I have some questions as below:

Q1: What happens with the DOM tree of the page1.html, will it be unloaded and reloads latter when we navigate back to it from the page2.html? Can I reference DOM tree of the page1.html from page2.html?

Q2: If I'm maintaining a socket connection in a socket object in the page1.html, can I pass that socket object to page2.html? Can I listen for events of that socket object in page2.html?

Q3: Can I have a common object of both page1.html and page2.html. And I can do something like maintaining a timer to do common task for both page1.html and page2.html in that object? This object is like singleton object in other OOP language.

Answer 1

Q1: What happens with the DOM tree of the page1.html, will it be unloaded and reloads latter when we navigate back to it from the page2.html?

More or less. Browsers cache previously visited pages and probably won't fire a new load event when revisited using "back" navigation. Some will keep the page in its previous state, some wont.

Can I reference DOM tree of the page1.html from page2.html?

No. From a DOM point of view, page1.html has ceased to exist.

Q2: If I'm maintaining a socket connection in a socket object in the page1.html, can I pass that socket object to page2.html?

No, but you may be able to serialise it when page1 closes, send it to the server, then include it in page2 where it can be restored ( cf JSON).

Can I listen for events of that socket object in page2.html?

Not if it's still in page1 , but you may be able to emulate that behaviour on the server.

Q3: Can I have a common object of both page1.html and page2.html.

Not using javascript. However, if you passed the object to page2 (say via serialisation or some other method via the server) then you can perhaps pass it back again.

And I can do something like maintaining a timer to do common task for both page1.html and page2.html in that object?

No, but again you can do such stuff server side.

This object is like singleton object in other OOP language.

Cool.

If you describe what you are actually trying to do (ie the outcome you are trying to achieve rather then the method you are using to do it), a suitable architecture or design pattern might be suggested, eg as Abhi has intimated, a one page application may suit.