Extjs ajax synchronous request post method parameter sending method_extjs

Ajax synchronization requests generally look like this:

General parameters can be passed through the url followed by the background. However, you can also send parameters when you see the send parameter. I tried it on the server side. The parameters sent cannot be accepted. In Firebug, I see that the post part of the request sent is a string, which does not look like the parameters sent normally. After searching for a long time, I still couldn't find a method. Later I found an article that introduced the explanation of the send method of the xmlHttpRequest object, and then I realized that I need to set a header attribute Content-Type to tell the server to send data in form, and then the parameter string in the send method will be Interpreted by the server.