Re: [Dorset] Client Side Scripting of Web Pages
On 24/10/13 17:22, Terry Coles wrote: So here's the question. Are there numerous ways to do this and if so, does every browser have its own way? OK, so we discussed this further at work and homed in on the real question: I understand that all browsers speak Javascript, so a page containing js, just gets executed. What if the script is written in PERL, PHP or even TCL or Python? Presumably the page includes a mime type, but how does the browser know what package to use to execute the code. We appreciate that the OS knows what to do with these languages because its file associations settings, but my colleague believes that he has monitored all of the activity when a browser loads a page with referenced scripts on it and the browser never calls the OS. What have we missed? Terry -- Next meeting: Bournemouth, Tuesday, 2013-11-05 20:00 Meets, Mailing list, IRC, LinkedIn, ... http://dorset.lug.org.uk/ New thread on mailing list: mailto:dorset@mailman.lug.org.uk How to Report Bugs Effectively: http://goo.gl/4Xue
Re: [Dorset] Client Side Scripting of Web Pages
Hi Terry, Terry Coles wrote: I understand that all browsers speak Javascript, Except those that don't, e.g. lynx(1). :-) so a page containing js, just gets executed. What if the script is written in PERL, PHP or even TCL or Python? Presumably the page includes a mime type, but how does the browser know what package to use to execute the code. Well, the browser has a list of MIME types and how to handle them for other things, e.g. audio formats. You can edit it to use external programs, for example. But are you getting confused between code that's shipped as part of, or referenced by, a HTML web page and code that responds to a HTTP request from a browser on the server? That back-end code can be written in anything and the browser doesn't know or care. Andrew Montgomery-Hurrell wrote: Most browsers just fail if you use any language other than javascript. There's a version of Chromium that supports Dart natively AIUI. For other browsers, you load some Javascript that can handle the Dart. https://www.dartlang.org/docs/tutorials/connect-dart-html/#about-html-code script type=application/dart src=mini.dart/script script src=packages/browser/dart.js/script I'm not entirely sure browsers even expose a useful enough API to be able to develop a useful plugin to do that. I think they do? I've vague recollections of being able to add a Python interpreter to Internet Explorer some years ago when web scripting languages first made an appearance. Cheers, Ralph. -- Next meeting: Bournemouth, Tuesday, 2013-11-05 20:00 Meets, Mailing list, IRC, LinkedIn, ... http://dorset.lug.org.uk/ New thread on mailing list: mailto:dorset@mailman.lug.org.uk How to Report Bugs Effectively: http://goo.gl/4Xue
Re: [Dorset] Client Side Scripting of Web Pages
Some browsers do expose an API allowing these things, but my point is more that I'm not convinced they provide anything that allows someone to add in support for other languages that is useful in anyway beyond simple toys. Regarding Python in the browser, this site has some useful info: https://wiki.python.org/moin/WebBrowserProgramming I'm wondering as to _why_ you even want to run scripts in another language client-side. Any such language would (assuming the browser support API also sandboxes it's code) be limited to only effecting changes in the browser environment, so there isn't really any utility to using another language over javascript. If you want to be able to run scripts that do other things outside of that sandbox (such as a script that runs an application on the user's computer and displays it's output in the browser), then there are a whole bunch of security implications there which need to be considered. On 25 October 2013 14:26, Ralph Corderoy ra...@inputplus.co.uk wrote: Hi Terry, Terry Coles wrote: I understand that all browsers speak Javascript, Except those that don't, e.g. lynx(1). :-) so a page containing js, just gets executed. What if the script is written in PERL, PHP or even TCL or Python? Presumably the page includes a mime type, but how does the browser know what package to use to execute the code. Well, the browser has a list of MIME types and how to handle them for other things, e.g. audio formats. You can edit it to use external programs, for example. But are you getting confused between code that's shipped as part of, or referenced by, a HTML web page and code that responds to a HTTP request from a browser on the server? That back-end code can be written in anything and the browser doesn't know or care. Andrew Montgomery-Hurrell wrote: Most browsers just fail if you use any language other than javascript. There's a version of Chromium that supports Dart natively AIUI. For other browsers, you load some Javascript that can handle the Dart. https://www.dartlang.org/docs/tutorials/connect-dart-html/#about-html-code script type=application/dart src=mini.dart/script script src=packages/browser/dart.js/script I'm not entirely sure browsers even expose a useful enough API to be able to develop a useful plugin to do that. I think they do? I've vague recollections of being able to add a Python interpreter to Internet Explorer some years ago when web scripting languages first made an appearance. Cheers, Ralph. -- Next meeting: Bournemouth, Tuesday, 2013-11-05 20:00 Meets, Mailing list, IRC, LinkedIn, ... http://dorset.lug.org.uk/ New thread on mailing list: mailto:dorset@mailman.lug.org.uk How to Report Bugs Effectively: http://goo.gl/4Xue -- Andrew Montgomery-Hurrell Professional Geek Blog: http://darkliquid.co.uk Twitter: http://twitter.com/darkliquid Fiction: http://www.protagonize.com/author/darkliquid -- Next meeting: Bournemouth, Tuesday, 2013-11-05 20:00 Meets, Mailing list, IRC, LinkedIn, ... http://dorset.lug.org.uk/ New thread on mailing list: mailto:dorset@mailman.lug.org.uk How to Report Bugs Effectively: http://goo.gl/4Xue
Re: [Dorset] Client Side Scripting of Web Pages
Hi Terry, So if we want to use a browser to execute a script that isn't js, there's no reliable way to do it that would work across all platforms / browsers. Add some Javascript to interpret it or produce equivalent Javascript on the fly. :-) You alternative is to also ship a web server specific to your task that they run on their local machine and your web pages access on its port using localhost. This can be written in anything that will run on the platforms you support, e.g. Python, Go, ... An example is Python's SimpleHTTPServer module, which is a library that can be imported into your own code; it can also be run as a standalone program which makes it serve the files rooted at the current directory. In one window... $ ls hello.html pi.txt $ python /usr/lib/python2.6/SimpleHTTPServer.py Serving HTTP on 0.0.0.0 port 8000 ... In another... $ curl -sS http://localhost:8000/pi.txt 3.14159265358979323844 $ lynx -dump http://localhost:8000/hello.html Man who set type, risk becoming galley slave. $ It maps file suffixes onto the MIME types for the Content-type header. $ curl -sSI http://localhost:8000/hello.html HTTP/1.0 200 OK Server: SimpleHTTP/0.6 Python/2.6.6 Date: Fri, 25 Oct 2013 13:42:50 GMT Content-type: text/html Content-Length: 123 Last-Modified: Fri, 25 Oct 2013 13:40:30 GMT $ curl -sSI http://localhost:8000/pi.txt HTTP/1.0 200 OK Server: SimpleHTTP/0.6 Python/2.6.6 Date: Fri, 25 Oct 2013 13:42:56 GMT Content-type: text/plain Content-Length: 23 Last-Modified: Fri, 25 Oct 2013 13:39:06 GMT $ Your server would run its own logic rather than just serve static files. Cheers, Ralph. -- Next meeting: Bournemouth, Tuesday, 2013-11-05 20:00 Meets, Mailing list, IRC, LinkedIn, ... http://dorset.lug.org.uk/ New thread on mailing list: mailto:dorset@mailman.lug.org.uk How to Report Bugs Effectively: http://goo.gl/4Xue
Re: [Dorset] Client Side Scripting of Web Pages
Hi Andrew, I'm not convinced they provide anything that allows someone to add in support for other languages that is useful in anyway beyond simple toys. They would be as useful as Javascript, I imagine. I'm wondering as to _why_ you even want to run scripts in another language client-side. Will, things like: corporate demands; lack of Javascript knowledge in-house; numerical code would like integers, not just floating-point doubles; dislike of Javascript -- something drove Coffeescript and Dart to exist :-). Any such language would (assuming the browser support API also sandboxes it's code) be limited to only effecting changes in the browser environment Just like Javascript, yes. They just don't want to use it or already have lots of useful library code in another language. Cheers, Ralph. -- Next meeting: Bournemouth, Tuesday, 2013-11-05 20:00 Meets, Mailing list, IRC, LinkedIn, ... http://dorset.lug.org.uk/ New thread on mailing list: mailto:dorset@mailman.lug.org.uk How to Report Bugs Effectively: http://goo.gl/4Xue
Re: [Dorset] Client Side Scripting of Web Pages
Thanks Andrew and Ralph, I'll report back to my colleagues on Wednesday (I'm out Mon / Tues next week) and see what the consensus is. Stand by for the next thrilling instalment :-) For your information, I'm more of a go-between here, but my colleagues want to be able to create documentation / tools that customers can view with a standard browser on any platform. We have no prior experience of javascript, but we do of quite a few other scripting languages, (such as TCL), so there are some cost savings to be had if we write / cull code that we already have rather than writing something completely from scratch in an unfamiliar language. We also have tools that can generate code automatically from key parameters / attributes, but they don't do javascript :-( A reliable way for the browser to invoke the necessary tool would be ideal, but maybe something server side could work. however, we would have to ship the server because these tools do not always have access to the internet. Terry On 25/10/13 15:31, Andrew Montgomery-Hurrell wrote: That makes sense. There are a few projects (like PyJS or phpjs) that can compile a subset of another language into javascript which might be usable in those scenarios, but you lose the benefits of, say, proper numerical typical, etc in that case since it's still javascript at the end of the process. On 25 October 2013 14:59, Ralph Corderoy ra...@inputplus.co.uk wrote: Hi Andrew, I'm not convinced they provide anything that allows someone to add in support for other languages that is useful in anyway beyond simple toys. They would be as useful as Javascript, I imagine. I'm wondering as to _why_ you even want to run scripts in another language client-side. Will, things like: corporate demands; lack of Javascript knowledge in-house; numerical code would like integers, not just floating-point doubles; dislike of Javascript -- something drove Coffeescript and Dart to exist :-). Any such language would (assuming the browser support API also sandboxes it's code) be limited to only effecting changes in the browser environment Just like Javascript, yes. They just don't want to use it or already have lots of useful library code in another language. Cheers, Ralph. -- Next meeting: Bournemouth, Tuesday, 2013-11-05 20:00 Meets, Mailing list, IRC, LinkedIn, ... http://dorset.lug.org.uk/ New thread on mailing list: mailto:dorset@mailman.lug.org.uk How to Report Bugs Effectively: http://goo.gl/4Xue -- Next meeting: Bournemouth, Tuesday, 2013-11-05 20:00 Meets, Mailing list, IRC, LinkedIn, ... http://dorset.lug.org.uk/ New thread on mailing list: mailto:dorset@mailman.lug.org.uk How to Report Bugs Effectively: http://goo.gl/4Xue
