Click a button using jQuery and append data to response after ajax success

I have two buttons and one of them is already bound with an ajax call from a different site. I need to call the ajax using the first button and also I need to append some data to the result after ajax completion.

(Unfortunately, I have no access to edit the ajax function or existing jQuery. All I can do is that create a new function).

Simply I need to call this from the console. Is there any jQuery function to know whether an ajax is called and that one has a success response?

I tried to use ajaxStart() and ajaxStop(), but not working.

This what I tried:

jQuery('.a').click(function(){
  var valuetopass;
  //Copy Value from input of A
  jQuery(document).ajaxStart(function(){
    console.log('Click Ajax Button');
    valuetopass = jQuery('.a_value').val();
  });

  //Call Ajax
  jQuery('.b').click();

  //Paste Value to the result appended
  jQuery(document).ajaxStop(function(){
    console.log('Appended the result input field(b_value) to the html.');
    
    //Paste the value in new field from ajax.
    jQuery('.b_value').val(valuetopass);
  });
});

<input class="a_value" value="ABC"/>
<button class="a">Button to initiate ajax</button>
<button class="b">Button having Ajax</button>

Here when we click on button A it will initiate a click on button B and ajax will call. After that, the result will append an input field in HTML like <input class="b_value"/> . I need to add value to this field using an external jQuery function.

I have also tried

setTimeout(function(){
  jQuery('.b_value').val(valuetopass)
},500);

But we can't say 500 ms will be the exact time taken. Is there any possibility to find the ajax called and finished?

You can use .ajaxComplete(), use it like this

$( document ).ajaxComplete(function(event, xhr, settings) {
  console.log(xhr.responseText);
});

Here xhr.responseText will be having the response of every ajax call made by jQuery ajax method. So your response <input class="b_value"/> can be processed inside this callback