how to pass value from javascript to java in jsp

[john woo]

Hi

in JSP, it's easy to pass value from java-variable to
javascript-variable, like

js_function(a)
{ a=<%java-class.A%>
}

I'm wondering how is the other way around? I tried

js_function(a)
{ <%java-class.A=%>a
}

but there was compiling error.

Can any one help?

--
Thanks
John
Toronto

[Yereth]

Re: how to pass value from javascript to java in jsp

You can only pass from JSP to JS in your code. If you want to pass
variables the other way around then you'll have to use the POST or GET
method, because JSP is serverside and JS clientside, which means that
first, on the server, JSP is executed (it generates HTML and other
clientside code, like PHP does) and second, that the generated source
document is sent to the client where possible scripting languages like
JS and VBS are executed.

Hope that helps.

Cheers,
Yereth

[Lasse Reichstein Nielsen]

Re: how to pass value from javascript to java in jsp

"john woo" <john_woo@canad a.com> writes:
[color=blue]
> in JSP, it's easy to pass value from java-variable to
> javascript-variable, like
>
> js_function(a)
> { a=<%java-class.A%>
> }[/color]


Notice what happens here: The java is evaluated and inserted
in something that is just text. It happens to be a Javascript
program, but the JSP template engine doesn't really care.
To the server, where this runs, it's just text and Java.
The output of the template is just text.
[color=blue]
> I'm wondering how is the other way around? I tried
>
> js_function(a)
> { <%java-class.A=%>a
> }[/color]

The server doesn't care whether you write that or this:

argleebargle <%java-class.A=%> glop glyf

It's still just malformed Java and random text to it.


The javascript is run on the client, i.e., in the browser. At that
time, the Java is long gone, and only the output of the template
remains. If you want to bring a value from the javascript, running
on the client, to Java, running on the server, you need to send
it to the server somehow - as part of an HTTP request.

/L
--
Lasse Reichstein Nielsen - lrn@hotpop.com
DHTML Death Colors: <URL:http://www.infimum.dk/HTML/rasterTriangleD OM.html>
'Faith without judgement merely degrades the spirit divine.'

[Thomas 'PointedEars' Lahn]

Re: how to pass value from javascript to java in jsp

Yereth wrote:
[color=blue]
> You can only pass from JSP to JS in your code. If you want to pass
> variables the other way around then you'll have to use the POST or
> GET method, because JSP is serverside and JS clientside, [...][/color]

The JS is probably client-side *here*.


PointedEars
--
Bill Gates isn't the devil -- Satan made sure hell
_worked_ before he opened it to the damned ...