Server communication without page reload?

[Kurita Kinoshita]

I'm trying to find a way to have a script communicate with a server
without having to load a new page. The idea is to have the server act
as a simple wrapper for a database, letting the client do that icky UI
stuff.

I tried the obvious, putting a frame somewhere it doesn't insult the
eye, changing its location, then accessing the new content via DOM.
What I get from IE (6) for my pains is just a rude "permission
denied". This even though I entered "localhost" as a trusted site in
IE's security setting. What's amiss?

Help from one of you pros out there would be greatly appreciated! ;-)

TIA,
Kurita

ci***********@gmx.net

[Si Ballenger]

On 14 Jun 2004 07:27:31 -0700, ci***********@gmx.net (Kurita
Kinoshita) wrote:

I'm trying to find a way to have a script communicate with a server
without having to load a new page. The idea is to have the server act
as a simple wrapper for a database, letting the client do that icky UI
stuff.

I tried the obvious, putting a frame somewhere it doesn't insult the
eye, changing its location, then accessing the new content via DOM.
What I get from IE (6) for my pains is just a rude "permission
denied". This even though I entered "localhost" as a trusted site in
IE's security setting. What's amiss?

Help from one of you pros out there would be greatly appreciated! ;-)

Not a pro, but if you don't want the page to reload, then you can
use the status: 204 http code to tell the brouser to not expect
to reload the page. I use it on my pages below to run programs on
my server with out having a page refresh, in this case to operate
pan and tilt webcams.

http://www.geocities.com/zoomkat/ppswitcher-demo.htm
http://www.geocities.com/zoomkat/ezservo1.htm

[Vincent van Beveren]

> I tried the obvious, putting a frame somewhere it doesn't insult the

eye, changing its location, then accessing the new content via DOM.
What I get from IE (6) for my pains is just a rude "permission
denied". This even though I entered "localhost" as a trusted site in
IE's security setting. What's amiss?

Thats weird,it should be accessable. Did you initialize the FRAME
before modifying its contents? I found that you normally first need
to load an SRC="about:blank" before you can access its properties
(like window.location). The corret path to the window object of
a frame would be document.frames[0].contentWindow. You can also use
XML to communicate. Maybe that would even be better.

Good luck,
Vincent

[Vladdy]

Kurita Kinoshita wrote:

I'm trying to find a way to have a script communicate with a server
without having to load a new page. The idea is to have the server act
as a simple wrapper for a database, letting the client do that icky UI
stuff.

I tried the obvious, putting a frame somewhere it doesn't insult the
eye, changing its location, then accessing the new content via DOM.
What I get from IE (6) for my pains is just a rude "permission
denied". This even though I entered "localhost" as a trusted site in
IE's security setting. What's amiss?

Help from one of you pros out there would be greatly appreciated! ;-)

TIA,
Kurita

ci***********@gmx.net

There are several options that can be used. The choice depends on the
amount and type of data that is being sent back and forth.
1. Loading file via XMLHTTP. The following function will return any type
of text data that you parse with client side script. The filename you
pass is the name of your server side script and can contain query string
that allows you to pass limited amount of data to the server:

function getFile(filename)
{ oxmlhttp = null;
try
{ oxmlhttp = new XMLHttpRequest();
oxmlhttp.overrideMimeType("text/xml");
}
catch(e)
{ try
{ oxmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
}
catch(e)
{ return null;
}
}
if(!oxmlhttp) return null;
try
{ oxmlhttp.open("GET",filename,false);
oxmlhttp.send(null);
}
catch(e)
{ return null;
}
return oxmlhttp.responseText;
}

2. Similar to the method above you can dynamically create a script node:

function loadJS(filename)
{ scriptNode = document.createElement('script');
scriptNode.src = filename;
scriptNode.type = 'text/javascript';
(document.getElementsByTagName('head'))[0].appendChild(scriptNode);
}

Again filename is your server side script and can contain query string
as well. The difference is that the server side script has to return
javascript (make sure you set the MIME type header to
"text/javascript"). Compared to the first method you receive data ready
to be used.

3. If you have siginificant amount of data to pass to the server, you
would need a hidden iframe so that you can use POST method.

--
Vladdy
http://www.klproductions.com