JS在Chrome浏览器中showModalDialog函数返回值为undefined的解决方法

<script type="text/javascript">
function SelectGroupCust() {
  var temp = window.showModalDialog("Default2.aspx" + Date(), "", "dialogWidth=800px;dialogHeight=600px;help=no;center=yes;");
  //for chrome
  if (temp == undefined) {
    temp = window.returnValue;
  }
  alert(temp);
  return true;
}
</script>

<script language="javascript" type="text/javascript">
function ReturnAddressee() {
  if (window.opener != undefined) {
    window.opener.returnValue = "1";
  }
  else {
    window.returnValue = "2";
  }
  window.close();
}
</script>