A META header in the <Head> section of the HTML page can force a recurrent refresh. The first article Google found on the subject is this one: http://www.htmlgoodies.com/tutorials/getting_started/article.php/3479551 The article also shows a micro-snippet in JavaScript to obtain a similar effect on a user click.
In order to obtain a similar effect under program control, where the server decides when it's time to upgrade, one needs to keep a channel opened between the browser and the server. This implies tricky JavaScript code client-side and tricky code server side. Modern browser can leverage so-called websockets (https://en.wikipedia.org/wiki/WebSocket) as long as the server is up to the game. There are fallback strategies (https://stackoverflow.com/questions/7807066/how-signalr-works-internally/7874352#7874352). In general, having a full-duplex communication between a browser and a web server is possible but it's not trivial and its complexity depends, among various other things, on the level of compatibility required. Personally, before embarking in anything more complex, I would try and see if the Meta Refresh tag is good enough. Good luck! -- Stefano -----Original Message----- From: Programming [mailto:programming-boun...@forums.jsoftware.com] On Behalf Of Raul Miller Sent: martedì 5 settembre 2017 14:54 To: Programming forum <programm...@jsoftware.com> Subject: Re: [Jprogramming] How can I auto-refresh a JHS app page? That's pretty much it. The browser is in control here, and jijx is only indirectly in control as a result. Probably the simplest would be to put something like Refresh: 3 in the http headers in your MYTEMPLATE (before the first blank line). But I haven't tested that - I probably need to upgrade my jhs implementation before your code would work for me. Thanks, -- Raul On Tue, Sep 5, 2017 at 8:27 AM, Ian Clark <earthspo...@gmail.com> wrote: > Currently I'm hacking it by using Keyboard Maestro to execute a timer which > reloads the message URL every 3 seconds. > > I guess much the same thing could be done using Javascript embedded in > message.ijs? – if I knew any Javascript. > > Another expedient is to write out the message display to a textfile > (~/message.txt) and open it using TextWrangler. This (unlike TextEdit) > refreshes its display window whenever message.txt is rewritten. > > But these expedients are inelegant. I guess web browsers were not designed > to do this sort of thing. (Or designed not to do this sort of thing?) > > On Tue, Sep 5, 2017 at 2:59 AM, Ian Clark <earthspo...@gmail.com> wrote: > >> Suppose I am a JHS coder, working with the J session (the jijx page), and >> have written an app called "message" (say). This generates a page of data >> in response to the URL: >> >> http://localhost:65001/message >> >> which I choose to display in a separate browser window. Let's call it the >> message window. >> >> If I execute some phrase in jijx which changes the content of the message >> window, then in the normal course of things I would need to manually reload >> the page in order to see the altered data. For example (in Safari) by >> activating the message window and clicking the symbol: "Reload this page". >> >> How can I write a verb (to be executed in jijx) which refreshes the >> message window without having to do that? >> >> > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
