//***************************************************************
// Javascript "Scroll to Top"
//***************************************************************

var g_USER_AGENT = getAgent();
		
		// return NN4, NN5(Netscape 6+, Mozilla 1+?), IE4, IE5(IE5+), Unknown
		function getAgent(){
		  var userAgent = navigator.userAgent;
		  var charIndex;
		  var majorVersion;
		
		  charIndex = userAgent.indexOf("MSIE");
		  if(charIndex){
			majorVersion = userAgent.charAt(charIndex + 4 + 1);
			if(majorVersion > 4){
			  return("IE5");
			}
			else if(majorVersion == 4){
			  return("IE4");
			}
		  }
		
		  charIndex = userAgent.indexOf("Mozilla");
		  majorVersion = userAgent.charAt(charIndex + 7 + 1);
		  if(majorVersion > 4){
			return("NN5");
		  }
		  else if(majorVersion == 4){
			return("NN4");
		  }
		
		  return("Unknown");
		}

function getWindowYOffset(){
		  if(g_USER_AGENT == "IE5" || g_USER_AGENT == "IE4"){
			return document.body.scrollTop;
		  }else if(g_USER_AGENT == "NN5" || g_USER_AGENT == "NN4"){
			return window.pageYOffset;
		  }else{
			return 0;
		  }
		}
		
		var waitTimer;
		function jumpTo(dstY, srcY, scrollRate, waitMillSec) {
		  if(waitTimer){
			clearTimeout(waitTimer);
		  }
		  if( ! dstY || dstY < 0 ){
			dstY = 0;
		  }
		  if( ! srcY ){
			srcY = 0 + getWindowYOffset();
		  }
		  if( ! scrollRate ){
			scrollRate = 5;
		  }
		  if( ! waitMillSec ){
			waitMillSec = 20;
		  }
		
		  srcY += (dstY - getWindowYOffset()) / scrollRate;
		  if(srcY < 0){
			srcY = 0;
		  }
		  posY = Math.floor(srcY);
		  window.scrollTo(0, posY);
		
		  if(posY != dstY){
			waitTimer = setTimeout("jumpTo("+ dstY +", "+ srcY +", "+ scrollRate +", "+ waitMillSec +")", waitMillSec);
		  }
		  else if(posY == dstY){
			clearTimeout(waitTimer);
		  }
		  else if(posY < 1){
			window.scroll(0, 0);
		  }
		}
		
		function toTop(){
		  jumpTo(0, 0, 7, 14);
		}