function setStartPage() {
     var b = document.body;
     var ua = navigator.userAgent;
     var ie = ua.indexOf("MSIE");
     var iever = parseInt(ua.substring(ie+5, ie+6));
     var os = ua.indexOf("Windows");
     if(ie > 0 && iever >= 5 && os > 0 && !window.opera){
	 var homepage = "http://mytown.japanet.jp";
	 var jumpto = "http://mytown.japanet.jp";
	 b.style.behavior = "url('#default#homepage')";
	 var is_home = 
	     b.isHomePage(homepage) || b.isHomePage(homepage + "/");
         if(is_home) 
             alert("livedoor はすでにスタートページに設定されています。");
         else 
             b.setHomePage(homepage + "/");
	 is_home = 
	     b.isHomePage(homepage) || b.isHomePage(homepage + "/");
	 if(is_home) {
	     document.location.replace(jumpto);
	 }
     }
     else {
         document.location.href="http://mytown.japanet.jp";
     }
}