The good news is that Edge, the browser that ships with Windows 10, and Internet Explorer 10 fully support the W3C specification for CORS, and you can use standard techniques with XmlHttpRequest (XHR) and CORS headers. Internet Explorer 7 and older versions do not support CORS at all.
According to Can I Use... (as of August 2015), CORS is supported by 97.69% of browsers in the USA and 92.76% globally. For more information about CORS support in browsers, see the Can I Use... page for CORS: .
In Internet Explorer 8 and 9, you have to use feature detection and XDomainRequest instead of XHR. We covered using XDomainRequest in Chapter 1, Why You Need CORS.
The following example shows how to detect XHR withCredentials and XDomainRequest support. If a new XmlHttpRequest has "withCredentials", then CORS is supported; if the window has XDomainRequest, then that method is supported; if neither is present, you cannot use CORS:
function browserSupportsCors...
