I want to activate the back button of the HTML-browser. with a JAVA command not Javascript.
does anyone know how?
Assuming you are talking about an applet: I assume you would have to use the netscape.javascript packages to hit the JS API for it.
If you are talking about server side Java, then you have no way to trigger the back functionality. The closest you could come would be to read the referer (warning: Optional! Sometimes forged! Make sure it is a URI on your domain!) and issue a Location header to redirect forwards to it.
You can't. Java runs on the server. JavaScript runs on the client. You could have a JSP output JavaScript which is then run at client time in the browser.
Related
I'm building my own HTTP server in java, but i'm facing with a problem: I would like to build a page dynamically by creating every HTML object at runtime, the question is: how can i determine the screen dimension of the client's browser?
This information is not present in the HTTP header, so I was thinking about writing a "fake" webpage that runs a javascript that tells the server about the screen (it should redirect to something like www.website.com/w:1920,h:1080) but I don't know anything about cookies (that I suppose are essential to store those informations).
Do you think that I should learn somthng about cookies or there's another way?
BTW I'm not using servlets, just Socket, because that's what I know... should I use servlets?
Thanks for your time!
Matteo
Server knows nothing about client's screen until client send this information. Javascript is easiest way to determine screen size:
window.screen.availHeight
window.screen.availWidth
AJAX request can be used to send the information to the server where it can be stored in session data and backed in database for example if the user is logged in or identified somehow. In such case you don't need cookies. However solution with cookies is easier, check how to set them via javascript. But I'm afraid such solution would be a bit of non-standard, if your site is gonna depend on javascript why not to use it extensively and generate all objects on client side, get that lazy computer working and save your server's resources :) Just feed data by sending simplest HTML containing script doing the work.
Servlets? Can be really light-weight and done with minimal knowledge if you have time go for it.
I have a JS program handling the communication from iframe to its parent. I am logging the different states on browser window (Inspect element's) console. How could i fetch these state values into my java program for validating/testing. The values are passed from JS in html file. Or if anyone can suggest any other way to validate the communication between parent and iframe.
Any suggestion or guidance will be helpful to move forward, I am stuck.
Thanks alot!!
Browser make http requests - so try implementing a basic http server in your java program and have the browser make ajax calls to the program.
Wondering if anyone knows if there is a way to "return" something from a java web start application into the code on the website. For example say the user needed to select a location in the java application. This would then pass the location value back to the code on the webpage (which is php and javascript). I have figured out how to pass arguments into a program, but so far cannot figure out any way to get them out after much googling. Any help would be much appreciated, thanks.
In principle no, since the Webstart application can be running without any Website open at all.
But if your clients use the Java-plugin from 1.6.0_10 or later (and not Safari and some other browsers with special Java-handling), you can use a JNLP-enabled applet, which is able to do the same things as a Webstart application (i.e. loading files and such), and is always bound to a webpage. It then can use the Javascript-bridge, or simply a loadDocument with the right parameters to feed back information.
You can use URL or sockets to connect back to the "same-origin" host. You can also use BasicService to open a web page, possibly from a different server, in a browser (although this shouldn't be used to send information back, as it'll be a GET not a POST).
I have a webpage that has JavaScript in it. The script contains a method that updates the webpage. I also have a java UDP server. When I get some parameters from a client, I want to call the method in the javascript to update the page.
Is it possible to call methods in Javascript from Java source code? Any pointers?
Thanks!
EDIT: For Ajax, the "request" initiates from the webpage. I want something that can change the webpage by itself - without this request.
A more succinct question would be: Can I dynamically update a webpage from java source file?
In order to reading javascript result you need a browser runtime AFAIK (You cannot get javascript result through a raw socket). You have to include a browser (JTextPane should be able to do it) into your udp server.
DWR is the answer, but it seems dead with no progress for some months. I don't think so you can directly call JavaScript methods from Java without passing an Asynchronous call using Ajax.
I have no idea on how you would dynamically change your content of webpage without an request being passed.
This is what we wanted to do:
-Send co-ordinates from an android phone to a server
-Plot these on a map in a browser window
The complexity was - One 'box' was server for android, and client for google maps. And we needed some glue between these two functionalities.
We initially tried ActiveMQ but could not get it to work.
Due to time constraints, we were forced to explore other approaches... our end result isn't elegant, but it works.
We have a FIFO on the server to which the co-ordinates are written. On the same server, our map page is also hosted. On a button press, XMLHttpRequest is sent to the server. In response, a co-ordinate is dequeued and sent back, which is plotted on the map using google maps api.
I will be happy to share more details/answer questions...
I have developed a Java applet which opens a URL connection to some different server. The applet then retrieves contents of the HTML page and do some processing and then shows to user. Can I cross-compile it to JavaScript using GWT?
Cross compile: No.
Port: Probably. Depends on your constraints.
You won't be able to do a straight recompile and have it "just work" (GWT only supports a subset of the JRE and any UI stuff definitely isn't a part of it) but you might be able to port some of your logic over. If you're using XPath to pull content out of the page, that code most likely will need to be redone as well. There's a GWT wrapper for Sarissa that works pretty well.
Also, since the requested page is going to be on a different server, you'll need to set up some method of doing a cross site request. So either browser hacks or a proxy on the hosting server.