How to get all the values after : in the json

Question

I want to extract all the input values which is available in the JSON using JavaScript.

I want to extract the value which is coming after "InputFieldTitle1 :". I tried with substring but it is giving only InputFieldTitle1 value and not InputFieldTitle2.

"payload": "{input : {  
  InputFieldTitle1 : “Input1”, 
  InputFieldTitle2 : “Input2”, 
  },}"