JSFiddle - React, Tailwind, and code Playground
by Barbos
HTML
<img id="im" width="256" height="256"/>
<div id="sp"></div>
<form>
map:<input name="map" value="visicom_base"/><br/>
x: <input name="x" value="38324"/><br/>
y: <input name="y" value="22097"/><br/>
z: <input name="z" value="17"/><br/>
<input type="button" value="test" onClick="
var url =computeUrl(form.map.value,form.x.value,form.y.value,form.z.value);
document.getElementById('im').src=url;
document.getElementById('sp').innerHTML=url;
return false;
"/>
</form>
JavaScript
function computeUrl(mapName,x,y,z) {
var s = Math.floor(Math.random()*4)
var y = (1<<(z-1))-(Number(y)+1)
var url = 'http://tms'+s+'.visicom.ua/2.0.0/planet3/base/'+(z-1)+'/'+x+'/'+ y +'.png';
return url;
};