On 08/24/2010 11:38 PM, Adam Barth wrote:
This seems related to the "magic iframe" concept that was recently added in WebKit. Basically, magic iframe lets you move an iframe from one document to another without blowing away the JavaScript/DOM state of the iframe.
One thing not too clear in the "magic iframe" approach is that how session history works; how is the session history from the iframe merged to the new one, especially if the iframe moves to a new document.
Another thing, which is more implementation depended problem, is that how the plugin native widget reparenting works, in case the iframe uses plugins. -Olli The way this works is that the iframe remains "alive"
until the browser returns to the main event loop. If a living iframe gets added to a document, then it keeps all it's state. This feature is useful for sites like Gmail that have chat windows that can be opened from the main document. If the user closes the main document, the chat windows can adopt some iframe that keeps the proper state. Adam On Tue, Aug 24, 2010 at 1:30 PM, Ben Lerner<[email protected]> wrote:There seems to be a bit of disagreement among browsers about how event loops and iframes interact when an iframe is removed and then reinserted into its parent document. Consider the following two documents: the parent document has a button that removes or reattaches an iframe to the document, while the second simply sets an interval to update the page content. Page1.html: <!DOCTYPE HTML> <html> <body> <p><button onclick="toggleInDoc();">Show/hide</button></p> <iframe id="test" src="page2.html"></iframe> <script> var test = document.getElementById("test"); function toggleInDoc() { if (test.parentNode == null) document.body.appendChild(test); else document.body.removeChild(test); } </script> </body> </html> Page2.html: <!DOCTYPE HTML> <html> <body> <p id="test"></p> <script> window.setInterval(function() { document.getElementById("test").innerHTML += "."; }, 500); </script> </body> </html> Assume the user waits until the interval has fired several times, then presses the button, waits a while, and presses it again. There are three possible outcomes: 1. When the iframe is reattached, the inner page reloads. This seems to go beyond the wording of the spec, which says only "When an iframe element is first inserted into a document, the user agent must create a nested browsing context, and then process the iframe attributes for the first time." (This isn't the first time the iframe is inserted into the document, so we shouldn't process the iframe attributes again.) 2. The interval (and presumably, all events) in the iframe is paused while it's been detached (since the document is no longer fully active, but it also has not been discarded because of the global reference to its container element). 3. The interval (and presumably, all events) continues to fire while it's been detached, and the content of page2 will have changed while it's been detached from page1. So far, Chrome 6, Opera 10.6 and Firefox 3.6 follow #1, and IE 8 follows #3. My reading of the "fully active" clause of the spec leads me to expect #2. Which of these behaviors is the desired one? And/or, would it be desirable to permit authors to specify which behavior they intend? Thanks, ~ben
