如何在来自 php 的 ajax JSON 响应中的字符串中添加双引号

I receive a JSON response in an Ajax request from the server. This way it works:

{"a":"1"，"b":"hello‘kitty’"}

但我没有成功地在kitty左右加上双引号.

When I convert " to \x22 in the Ajax response, it is still interpreted as " by JavaScript and I cannot parse the JSON.

Should I also escape the \ and unescape later (which would be possible)?

How to do this?

Edit: I am not sure if i expressed it well: I want this string inside of "b" after the parse:

hello "kitty"

If necessary I could also add an additional step after the parse to convert "b", but I guess it is not necessary, there is a more elegant way so this happens automatically?

Edit2: The ajax page is generated by php. I tried several things now to create the value of b, all result in JSON parse error on the page:

  $b = 'hello "kitty"';      

  // no 1:
  //$b = str_replace('"',"\x22",$b);

  // or no 2:
  // $b = addslashes($b);  

  // or no 3: 
  $b = str_replace('"','\"',$b);

  echo '{ "a" : "1", "b" : "' . $b . '"}';

Edit3:此解决方案最终有效:

$b = 'hello "kitty"';      
$b = str_replace('"','\\"',$b); 
echo '{ "a" : "1", "b" : "' . $b . '"}';