$(document).ready(function(){
	var areaObj = $('#contentsArea');
	var followObj = $(".follow");
	var toPos =  $(window).scrollTop() +  $(window).height() -250 ;
	var limitPos = areaObj.height() - followObj.height();
	if(toPos >= limitPos) toPos =limitPos;
	else if(toPos < 100) toPos = 0;
	followObj.css("top", toPos + "px" );
	
	var followIntervalId = setInterval(function(){	
		var objectPos =  parseInt(followObj.css("top"));
		toPos =  $(window).scrollTop() +  $(window).height() -250 ;
		limitPos = areaObj.height() - followObj.height();
		if(toPos >= limitPos) toPos =limitPos;
		else if(toPos < 100) toPos = 0;
		followObj.css("top", (objectPos + (toPos - objectPos)/10) + "px" );
	},12);
});