jQuery使用$ .ajax（）访问远程站点

Question

I broke this down to the absolute simplest code that will not work. I made a simple Echo Test on my webservice that will take a string as a parameter and echo it back. I wrote the javascript code that I've been working on in order to access this method here:

http://jsfiddle.net/stephenbayer/CaHqY/9/

I really need to know, why I am getting an error, and why the only message I'm getting back is the error string "Error" from javascript. How do I fix this and get this working.

This is a web service that has been running using standard SOAP through WCF, and we had a client that requested access through javascript. Sounded crazy to me, but I didn't think it would be that difficult. I can not find any good clear information about getting these cross-domain calls to work at all.

Answer 1

You can't do a Cross-Domain Call via normal AJAX due to the Same Origin Policy, you need to do a JSONP -Call for that.

Perhaps you could use CORS but you need to be careful because then youmight be vulnerable to cross site scripting.

Answer 2

Modern browsers prevent cross-domain requests in order to protect users from XSS attacks.

To handle data coming from another domain, you need one of those 4 solutions :

• modified headers on the xml server side
• jsonp request and response
• a proxy so that your browser thinks that both domains are the same
• relaxed protection in the browser (not possible on all of them)

Note that the first 2 solutions involve to change the XML server.

Answer 3

http://james.padolsey.com/javascript/cross-domain-requests-with-jquery

good luck

Answer 4

The others are right. You have to use JSONP instead of JSON.

But there are an alternative:

Instead of using the ajax direct with the other domain, use it with your own domain, creating a new webservice in your server, using php for example.

Then, in your php ws you can call the external webservice and it will work. Use file_get_contents() .

I use it to get addresses codes using a public server:

$remote_data = @file_get_contents('http://republicavirtual.com.br/web_cep.php?formato=json&cep='.urlencode($_REQUEST['cep']));

echo $remote_data;

Answer 5

Your browser is stopping the request because of the same origin policy . You can only make an xhr (ie ajax) to the domain from where the javascript was loaded.