Remember where you've read on the webpage.Go there next time.

go2here.js

(function(){
	//if autoStart is false,press key(ctrl+shift+a) to remember position
	//if autoStart is true,remember position when page is scrolled(how?)
	var autoStart=false;
	var xposition=window.pageXOffset;
	var yposition=window.pageYOffset;
	//press shortcut key to remember
	if(!autoStart){
		document.addEventListener("keydown",function(){
			if((event.ctrlKey)&&(event.altKey)&&(event.keyCode==82)){
				localStorage.position=window.pageXOffset + "|" + window.pageYOffset;
				alert("Position Remembered.\nNext time I'll bring you here.");
			}
		},false);
	}
	else{
		document.addEventListener("scroll",function(){
			if(Math.abs(window.pageYOffset-yposition)>100){
				localStorage.position=window.pageXOffset + "|" + window.pageYOffset;
				xposition=window.pageXOffset;
				yposition=window.pageYOffset;
			}
		},false);
	}
	//when open again,scroll to the remembered position
	window.addEventListener("load",function(){
		var savedPosition=localStorage.position;
		if(savedPosition){
			savedPosition=savedPosition.split("|");
			window.scrollTo(savedPosition[0],savedPosition[1]);
		}
	},false);
	//delete saved position
	document.addEventListener("keydown",function(){
		if((event.ctrlKey)&&(event.altKey)&&(event.keyCode==68)){
			localStorage.removeItem("position");
			alert("Deleted.");
		}
	},false);
})();