如何实现跨域ajax请求

发现了有3种办法可以解决这个问题，

1. 设置浏览器的options, enable access data sources across domains.

2. JSONP via jQuery. "JSON with padding" (JSONP) 

3. CORS: Http cross-origin resource sharing.  set Access-Control-Allow-Origin to *

this is an extension to the standard XMLHttpRequest.

Internet Explorer 8 and 9 expose CORS via the XDomainRequest object, but have a full implementation in IE 10.  While Firefox 3.5 introduced support for cross-site XMLHttpRequests and Web Fonts, certain requests were limited until later versions. Specifically, Firefox 7 introduced the ability for cross-site HTTP requests for WebGL Textures, and Firefox 9 added support for Images drawn on a canvas using drawImage.

Related articles:

https://developer.mozilla.org/en-US/docs/Web/HTTP/Access_control_CORS

https://developer.mozilla.org/en-US/docs/Web/HTTP/Server-Side_Access_Control