请教怎么php怎么返回变量+组装html给ajax

请问如何php如何返回变量+组装html给ajax

function html($select,$name){
global $pagecon;
$a='1';
$b='2';
$result='';
$result.='

';
while($row=$select->fetch()){
$result.='
• ';
  $result.='