■スクリプト
<HTML>
<HEAD>
<TITLE>Sample</TITLE>
<SCRIPT Language="JavaScript">
<!--
newWin = window.open("Dummy.htm","Sample","width=200,height=200");
sw = 0;
timeID = 0;
function change(){
sw = sw ^ 1;
if (sw) newWin.focus(); else newWin.blur();
clearTimeout(timeID);
timeID = setTimeout("change()",500);
}
// -->
</SCRIPT>
</HEAD>
<BODY bgColor="white" onLoad='timeID = setTimeout("change()",500);'>
<CENTER>
<H1>ウィンドウを背面に移動します</H1>
</CENTER>
</BODY></HTML>