Question

Hy,

I’m working on a jsFiddle with a openlayers example in it.
http://dev.openlayers.org/releases/OpenLayers-2.11/examples/snapping.html

At the moment it’s not working because it’s not getting a response for the http request to get data. How do I fix that?

The jsFiddle is here: http://jsfiddle.net/TcuxA/6/
Go to the line “// create three vector layers” in the script.
There are 3 requests for data. If you type the URLs in your browser you get the JSON, but my firebug gives 3 errors when I run the jsFiddle.

I tried fixing with jsFiddle echo ( http://doc.jsfiddle.net/use/echo.html ), but that didn’t work. I don’t know how to change the script to load the data otherwise.

Why can’t I get the json by these URLs? What are good sollutions?

Answer 1

What you are experiencing is an exception being thrown by the XMLHttpRequest object, because you are using AJAX to call elements from different domain. This is better said, for example, in here:

“The XMLHttpRequest object is prevented from calling web services from outside its own domain. This is sensible given that if you called a script in one place and it, in turn, called a script on another server, it could leave an application open to all sorts of malicious scripts, hacks and exploits.”

So the easiest way to do is to code it locally and call a local copy of the files (poly.json, line.json and point.json) that would reside on your local server. For testing if all displays on a map you could hard-code the files into your code. I am not sure how it could be achieved otherwise.