jquery Ajax Backend Response succeeded, returning the correct JSON but not executing the Success method, performing an error problem

I was stuck with the problem for hours yesterday. To view the HTTP status code: 200, and return the expected JSON string. however, the error method is executed and the success method is not Executed. Check on the internet, only to find that the background page returned the JSON string format is not correct, my error is the colon ":" is written as a comma ",". There will be the Ajax front-end JS code directly invoke the method in the error, such as the Problem.

You can go to the JSON online verification Web site to see if your JSON string is correct, if it is the JSON toolkit generated by the JSON string is not a Problem.

jquery Ajax Backend Response succeeded, returning the correct JSON but not executing the Success method, performing an error problem