<script>  
       var x = 0;    
       var y = 0;
       const krok = 64;
       const polomer = 64; 
       var smile; 
         
       function vytvoritObrazek(id) {
            var img = document.createElement("img");
            img.id = "euro" + id;
            img.src = "img/euro.png";             
            img.style.position = "absolute";
            img.style.left = (Math.round(Math.random()*300) + polomer).toString() + "px";   
            img.style.top = (Math.round(Math.random()*300) + polomer).toString() + "px";                    
            var stranka = document.getElementById("stranka");
            stranka.appendChild(img);              
       }
       
      function pohyb(event) {
          var x = event.clientX;
          var y = event.clientY;
          smile.style.left = x - krok/2 + "px";
          smile.style.top = y - krok/2 + "px";           
          //console.log(x, y);                              
      }
       window.onload = function() {       
           smile = document.getElementById('smile');
           vytvoritObrazek(0);           
           console.log(document.getElementById('euro0').style.left);
       }  
    </script> 
  

    <div style="height:100vh;" id="stranka" onmousemove="pohyb(event)">
      <img src="img/smile.png" id="smile" width="64" height="64" style="position:absolute; left:0px; top:0px;">
    </div>
  
<!--       
        if (Math.sqrt(Math.pow(x - xeuro, 2) + Math.pow(y - yeuro, 2) < 2*polomer)) {
           xeuro = Math.round(Math.random()*300) + polomer;
           yeuro = Math.round(Math.random()*300) + polomer;        
           euro.style.left = xeuro + "px";
           euro.style.top  = yeuro + "px";                             
        }       
-->