IE中的AJAX问题

I'm using a couple of ajax requests to:

a) Repeatedly (indirectly) call a php function:

function refresh_handler() {
                $.ajaxSetup({ cache: false});
    function refresh() {
        $.post('myPHP.php', null, function(data, textStatus) {
           $("body").html(data);
        });
    }
    setTimeout(refresh, 5000);
}

$(document).ready(refresh_handler); 

b) Get some SQL done (in a separate file to handle lots of jquery):

$.post('validate.php', {phpArray: arr}, function(data){
    $('#result').html(data);
  }); 

Works perfectly fine in Chrome but not in IE11.

Have tried $.ajaxSetup({ cache: false}); and <meta http-equiv="X-UA-Compatible" content="IE=9"> But it doesn't make any difference.

Weird thing is that IE acknowledge the meta tag when I check the emulation tab / document mode, and it gets set to the version I specify, but it doesn't make any difference. When I manually change it (both IE8 and 9) page is displayed properly though. What's going on?

use it like:

$(document).ready(function(){refresh_handler();});