php json返回在响应时创建语法错误

I have looked at many posts here and elswhere on this error without success of resolving my error. In console the form data is being sent via json as expected to my php processing page, the php process is not returning any errors so I'm confident the process is completing. I have checked the way the result is formatted and cannot see anything wrong there, although I'm no expert at ajax/json so I could be wrong, Here is my codeI have looked at many posts here and elswhere o