Do search engines see ajax loaded content?

Question

Google

Good day.
The lion's share of the site is loaded ajax a second after the main page load, in this way

<script>
var t = setTimeout( function() {
$.ajax({
type: 'POST',
url: '/news.php',
 data: {
                    aj: '<?=$user['url']?>'
                    },
cache: true,
async: true,
success: function(html){
$(".news").append(html);
}
});
}, 1000 );
</script>

Will search engines see the content, will they index it well?

Answer 1

robots will not wait while the data is loaded
https://yandex.ru/support/webmaster/robot-workings...
https://support.google.com/webmasters/answer/81766...

Answer 2

Search engines see everything that is processed before window.onload is completed
. Further, js is not processed.
Ie, your option - will not work.
Use includeHTML to load .