Reload parent window from child window

if you want to simply reload the parent window of child window: This line code below is enough for that.

opener.location.reload(); 

if you want to reload parent window with query string (request) with old or new values. Following code will do the work.

if (opener.location.href.indexOf('?') > 0) {
      var baseUrl = opener.location.href.substring(0, opener.location.href.indexOf('?'));
      opener.location.href = baseUrl + "?param1=abc&param2=123";
}
else {
      opener.location.href = opener.location.href + "?param1=abc&param2=123";
}

this opener.location.reload(); is not required in above example.

This will work for refresh parent window from child window

window.opener.location.reload(true);

for some version of IE this will not work so you can set some delay

window.setTimeout(window.opener.location.reload(true), 3000);

For Atlassian Connect Apps, use AP.navigator.reload();

See details here