You must define a CORS filter on your backend.
I don't know which language you are using but an example in spring framework (java) would be the following.
import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
@Component
@Order(Ordered.HIGHEST_PRECEDENCE)
public class SimpleCorsFilter implements Filter {
@Override
public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
HttpServletResponse response = (HttpServletResponse) res;
HttpServletRequest request = (HttpServletRequest) req;
response.setHeader("Access-Control-Allow-Origin", "*");
response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE, PUT");
response.setHeader("Access-Control-Max-Age", "3600");
response.setHeader("Access-Control-Allow-Headers", "x-requested-with, authorization, cache-control, content-type, Origin, key");
if ("OPTIONS".equalsIgnoreCase(request.getMethod())) {
response.setStatus(HttpServletResponse.SC_OK);
} else {
chain.doFilter(req, res);
}
}
@Override
public void init(FilterConfig filterConfig) {
}
@Override
public void destroy() {
}
}
Basically you are stating that response.setHeader("Access-Control-Allow-Origin", "*");
can come from any domain. ( in a production environment you would limit this offcourse to your known domains ).
When implementing this filter your options request will pass through without problems.
The options call is something the browser does automatically and you really don't want to disable this as some other answers are suggesting.
Kind regards