Screen repaint without leaving the execution context?

Is there any known trick to cause screen repaint without leaving the
execution context thus without using setTimeout workaround? On IE the
known way is

function _repaint() {
 window.showModalDialog('javascript:document.writeln('.concat(
  '"<script>', 'window.setTimeout(',
  'function(){window.close();},10);','<','/script>")'));

}

and then

function todo() {
 // DOM updates
 _repaint();
 // the rest of a lengthly process

}

Is any way to achieve the same functionality on Opera?