Using jQuery to alter an AJAX response

Well that depends on how you request the data. If you have $.ajax etc, then you can do the necessary modifications in the success handler. I assume since you don't understand jQuery very well, that you are using $.load() to load the data, in which case it's easiest to replace it with

$.get('/somecode.php', function(data) {
    data = $(data);

    // Find and remove all anchor tags for example
    data.find('a').remove();
    $('#target-id').append(data);
});

Or if you don't want to create a jQuery object, you can easily do something like

$.get('/somecode.php', function(data) {
    // Replace all strings "foo" with "bar" for example
    data = data.replace('foo', 'bar');

    // Manually append it to DOM or do whatever you want with it
    $('#target-id').append(data);
});

If you're using jquery 1.5+ you can use ajax datafilter.

dataFilter callback option is invoked immediately upon successful receipt of response data. > It receives the returned data and the value of dataType, and must return the (possibly > altered) data to pass on to success.

Sample Code :

$.ajaxSetup({
    dataFilter: function (response, type) {
        response = response.replace(/username/g, 'Sina Salek');
        return response;
    }
});

https://api.jquery.com/jquery.ajax/

in callback function, which looks something like

function(response){
  response = //edit response here
  $("#content").html(response);
}