JavaScript - que no reinicie al refrescar este código

<div id="number"></div>

<script>

var n = 0;

var l = document.getElementById("number");

window.setInterval(function(){

  l.innerHTML = n;

  n++;

},1000);

</script>

<div id="number"></div>

<script>

if(localStorage.getItem("tiempo") == null){

	localStorage.setItem("tiempo", (new Date()-0));

}

var n = parseInt(((new Date()-0)-parseInt(localStorage.getItem("tiempo")))/1000);

var l = document.getElementById("number");

setInterval(function(){

  l.innerHTML = n;

  n++;

},1000);

</script>

<div id="number"></div>

<script>

if(localStorage.getItem("tiempo") == null){

	localStorage.setItem("tiempo", (new Date()-0));

}

var n = parseInt(((new Date()-0)-parseInt(localStorage.getItem("tiempo")))/1000);

var sincro = 1000-1000*((((new Date()-0)-parseInt(localStorage.getItem("tiempo")))/1000)-(parseInt(((new Date()-0)-parseInt(localStorage.getItem("tiempo")))/1000)));

var l = document.getElementById("number");

setTimeout(function () {

	setInterval(function(){

	  l.innerHTML = n;

	  n++;

	},1000);

}, sincro);

</script>