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(function(window){
/* clears any divs we've created before */
function cl() {
// clear colours
var s=document.getElementsByClassName('fpser-lay');
var l = s.length-1;
for (var i=l;i>=0;i--) {
try {document.body.removeChild(s[i])} catch(e) {continue;}
}
// clear overlay
var e = document.getElementById('fpser'); // remove overlay if it's already there
if (e) e.parentNode.removeChild(e);
}
/* scrolls the page to the bottom */
function s2b() {
cl();
window.scrollTo(0,0); // reset screen position
count = 0;
sh = Math.max(document.documentElement.clientHeight, window.innerHeight || 0);
h = Math.max(document.body.offsetHeight,document.body.scrollHeight) - sh;
chunk = 100; // scrollwheel distance?
if (h - 100 < 0) {
alert ('I need to scroll, please reduce your browser height or choose a longer page!');
throw 'Too short';
}
fA=[];
window.requestAnimationFrame(sl);
ll=false;
}
/* scrolls the page by one scroll-wheel turn and gets framerate */
function sl() {
if (!ll) {
ll = performance.now();
window.requestAnimationFrame(sl);
return;
}
window.scrollBy(0,chunk);
tl = performance.now();
fA.push(parseInt(1000/(tl-ll)));
ll = tl;
count += chunk;
if (count >= h) {
window.scrollTo(0,0);
cF(fA);
} else {
window.requestAnimationFrame(sl);
}
}
/* creates the google chart API URL */
function spl(v) {
d=enc(v,100);
var w=350;
var g=1;
var cw=Math.max(parseInt((w/v.length)-g),2);
var url = "https://chart.googleapis.com/chart?chbh="+cw+","+g+"&cht=bvs&chxt=y&chf=bg,s,00000000&chs=350x60&chm=D,FF0000,1,0,2,1&chd=" + d;
console.log(url.length);
return url.substr(0,url.length-1);
}
var EM='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-.';
var EL=EM.length;
function enc(arrVals, maxVal) {
var cD = 'e:';
for(i = 0, len = arrVals.length; i < len; i++) {
// In case the array vals were translated to strings.
var numericVal = new Number(arrVals[i]);
// Scale the value to maxVal.
var scaledVal = Math.floor(EL *
EL * numericVal / maxVal);
if(scaledVal > (EL * EL) - 1) {
cD += "..";
} else if (scaledVal < 0) {
cD += '__';
} else {
// Calculate first and second digits and add them to the output.
var quotient = Math.floor(scaledVal / EL);
var remainder = scaledVal - EL * quotient;
cD += EM.charAt(quotient) + EM.charAt(remainder);
}
}
return cD;
}
/* creates overlays */
function cF(v) {
//v.shift();
var k = v.slice(0); // take a copy before sorting
// calculate median by sorting and select middle
v.sort( function(a,b) {return a - b;} );
var half = Math.floor(v.length/2);
if(v.length % 2)
var med = v[half];
else
var med = (v[half-1] + v[half]) / 2.0;
// min and max from sorted array
var mi = v[0];
var ma = v[v.length-1];
// mean by summing array and divide by total
var to = 0;
for (var i=0; i<v.length; i++) {
to+=v[i];
}
var mn = parseInt(to/v.length);
var c = spl(k);
// create the summary box
var d=document.createElement('div');
d.id='fpser';
d.style.cssText+=";font-family:sans-serif;font-weight:bold;width:400px;background:rgba(200,200,200,0.9);position:fixed;top:10px;right:10px;z-index:10002;padding:5px;box-shadow: 0px 0px 5px 2px rgba(0,0,0,0.75);text-align:center";
var p=document.createElement('p');
p.innerHTML='FPS: median = '+med + ', mean = '+mn + ', min = '+mi + ', max = '+ma;
p2=document.createElement('p');
if (med <= 50) {
p2.style.color="red";
p2.innerHTML="This page is JANKY (Framerate is below 50 FPS)";
} else if (med >= 59) {
p2.style.color="green";
p2.innerHTML="This page is SMOOTH (Framerate around 60 FPS)";
} else {
p2.style.color="yellow";
p2.innerHTML="This page is ALMOST JANKY (Framerate above 50 FPS)";
}
p3=document.createElement('p');
p3.innerHTML="<a href='https://webperf.ninja/2015/jank-meter'>What is this?</a> | <a href='#' onclick='window.FPS.cl();'>Hide this</a>."
// insert google chart image
var i=document.createElement('img');
i.src=c;
d.appendChild(p);
d.appendChild(i);
d.appendChild(p2);
d.appendChild(p3);
document.body.appendChild(d);
// create framerate indicator strip
var j=0;
for (var i = sh;i<=(h+sh);i+=100) {
var c = document.createElement('div');
c.className='fpser-lay';
var co = "";
if (parseInt(k[j])<50) {
co="255,55,0";
} else if (parseInt(k[j])<59) {
co="255,255,0";
} else if (parseInt(k[j])>0) {
co="55,255,55";
} else {
co="55,55,55";
}
c.style.cssText+=";border-bottom:1px solid black;line-height:"+chunk+"px;text-align:center;font-weight:bold;z-index:10001;position:absolute;width:80px;height:"+chunk+"px;left:0;top:"+i+"px;background:rgba("+co+",0.5);";
if (parseInt(k[j])>0) {
var m = document.createElement('p');
m.style.cssText+=";margin:0px";
m.innerHTML = k[j]+" FPS";
c.appendChild(m);
}
document.body.appendChild(c);
j++;
}
var c = document.createElement('div');
c.className='fpser-lay';
c.style.cssText+=";z-index:10001;position:absolute;width:80px;height:"+sh+"px;left:0;top:0;background:rgba(55,55,55,0.5);";
document.body.appendChild(c);
}
s2b();
window.FPS={};
window.FPS.cl=cl;
})(window);
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