# Is there a way to "catch" that someone refreshed page? **URL:** \ **Category:** Dash Python\ **Created:** [July 10, 2020, 11:19am UTC](https://community.plotly.com/t/is-there-a-way-to-catch-that-someone-refreshed-page/42288 "2020-07-10T11:19:31Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![patrykoz](https://avatars.discourse-cdn.com/v4/letter/p/ac8455/32.png) [@patrykoz](https://community.plotly.com/u/patrykoz)\ **Post date:** [July 10, 2020, 11:19am UTC](https://community.plotly.com/t/is-there-a-way-to-catch-that-someone-refreshed-page/42288/1 "2020-07-10T11:19:31Z")
As I wrote in topic - is there a way to catch that someone pressed F5? I need it to trigger the method. ---
**Author:** ![fohrloop](https://sea2.discourse-cdn.com/flex024/user_avatar/community.plotly.com/fohrloop/32/24888_2.png) [@fohrloop](https://community.plotly.com/u/fohrloop)\ **Post date:** [July 10, 2020, 1:12pm UTC](https://community.plotly.com/t/is-there-a-way-to-catch-that-someone-refreshed-page/42288/2 "2020-07-10T13:12:52Z")
If you make your layout to be a callable (function), then it is called every time the layout is created (every time the page is refreshed). So, instead of ```python layout = html.Div() app.layout = layout ``` use ```python def get_layout(): layout = html.Div() call_some_extra_function() return layout # Note: Not get_layout() app.layout = get_layout ``` ---
**Author:** ![patrykoz](https://avatars.discourse-cdn.com/v4/letter/p/ac8455/32.png) [@patrykoz](https://community.plotly.com/u/patrykoz)\ **Post date:** [July 13, 2020, 6:34pm UTC](https://community.plotly.com/t/is-there-a-way-to-catch-that-someone-refreshed-page/42288/4 "2020-07-13T18:34:02Z")
Thanks for response. Unfortunately - it doesn’t work for me. I have to add something to app.layout.children. So - it doesn’t exist during execution of get\_layout() ☹ Idea looks very well, so how to invoke my method after layout is assigned to app.layout? ---
**Author:** ![fohrloop](https://sea2.discourse-cdn.com/flex024/user_avatar/community.plotly.com/fohrloop/32/24888_2.png) [@fohrloop](https://community.plotly.com/u/fohrloop)\ **Post date:** [July 13, 2020, 6:56pm UTC](https://community.plotly.com/t/is-there-a-way-to-catch-that-someone-refreshed-page/42288/5 "2020-07-13T18:56:52Z")
What do you mean by having to add something to app.layout.children? ---
**Author:** ![patrykoz](https://avatars.discourse-cdn.com/v4/letter/p/ac8455/32.png) [@patrykoz](https://community.plotly.com/u/patrykoz)\ **Post date:** [July 13, 2020, 7:02pm UTC](https://community.plotly.com/t/is-there-a-way-to-catch-that-someone-refreshed-page/42288/6 "2020-07-13T19:02:48Z")
So I have app with hardcoded basic layout - few dcc.tabs. User can add new ones,then these are serialized and saved (in json). I do it by app.layout.children+=[newTab] and rest of functions. When I refresh page these tabs vanishing (but they are in json). When I shutdown app and restard these pages are loaded from json and they’re visible in layout. ---
**Author:** ![fohrloop](https://sea2.discourse-cdn.com/flex024/user_avatar/community.plotly.com/fohrloop/32/24888_2.png) [@fohrloop](https://community.plotly.com/u/fohrloop)\ **Post date:** [July 13, 2020, 7:10pm UTC](https://community.plotly.com/t/is-there-a-way-to-catch-that-someone-refreshed-page/42288/7 "2020-07-13T19:10:57Z")
What is the data type of `newTab`? Some dash component? Are you doing this inside a callback? Where is the “json” saved? Is the app going to be serving multiple users at the same time? ---
**Author:** ![patrykoz](https://avatars.discourse-cdn.com/v4/letter/p/ac8455/32.png) [@patrykoz](https://community.plotly.com/u/patrykoz)\ **Post date:** [July 13, 2020, 7:15pm UTC](https://community.plotly.com/t/is-there-a-way-to-catch-that-someone-refreshed-page/42288/8 "2020-07-13T19:15:34Z")
Just one user, I add dcc.Tab to layout, but I have also a function which returns object of my own class Tab (generally it’s html.div) if you click on one of dcc.Tab from layout. Yes, I do it in callback -json is saved in file in this same callback. ---
**Author:** ![fohrloop](https://sea2.discourse-cdn.com/flex024/user_avatar/community.plotly.com/fohrloop/32/24888_2.png) [@fohrloop](https://community.plotly.com/u/fohrloop)\ **Post date:** [July 13, 2020, 8:18pm UTC](https://community.plotly.com/t/is-there-a-way-to-catch-that-someone-refreshed-page/42288/9 "2020-07-13T20:18:08Z")
Do I understand this correctly: 1. App layout is created using app.layout = get\_my\_layout() 2. User presses button which is tied to a callback 3. Callback modifies app.layout.children. Something is added to `
` Why it could not be 1. App layout is a function app.layout = get\_my\_layout 2. User presses button which is tied to a callback 3. Callback Output is put to `
` ? ---
**Author:** ![patrykoz](https://avatars.discourse-cdn.com/v4/letter/p/ac8455/32.png) [@patrykoz](https://community.plotly.com/u/patrykoz)\ **Post date:** [July 15, 2020, 7:56pm UTC](https://community.plotly.com/t/is-there-a-way-to-catch-that-someone-refreshed-page/42288/10 "2020-07-15T19:56:43Z")
Yeah, I append straight to div instead append to children -and it’s okay. But app.layout = get\_my\_layout() is not invoked when user refresh a page 😕 ---
**Author:** ![fohrloop](https://sea2.discourse-cdn.com/flex024/user_avatar/community.plotly.com/fohrloop/32/24888_2.png) [@fohrloop](https://community.plotly.com/u/fohrloop)\ **Post date:** [July 16, 2020, 2:30pm UTC](https://community.plotly.com/t/is-there-a-way-to-catch-that-someone-refreshed-page/42288/11 "2020-07-16T14:30:30Z")
If you’re trying to have the layout to be reloaded every time the page is refreshed, you have to have **callable** (function) as `app.layout` So, instead of ```python app.layout = get_layout() ``` it should be ```python app.layout = get_layout ``` ---
**Author:** ![patrykoz](https://avatars.discourse-cdn.com/v4/letter/p/ac8455/32.png) [@patrykoz](https://community.plotly.com/u/patrykoz)\ **Post date:** [July 16, 2020, 8:21pm UTC](https://community.plotly.com/t/is-there-a-way-to-catch-that-someone-refreshed-page/42288/12 "2020-07-16T20:21:50Z")
Thanks a lot! It works!