javascript vine base station

<!doctype html>
<html>
<head>
    <title>javascript vine base station</title>

    <meta charset="utf-8" />
    <meta http-equiv="Content-type" content="text/html; charset=utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
</head>

<body>
<div>
    <h1>javascript vine base station</h1>
    <p>A somewhat grey hat page that will load and run any online javascript file you specify via <span id="haa" ></span>?JSL=[your javascript url here]<br>
<br>
If your script is code with no syntax errors and it's not a javascript mimetype file then you may need to prefix the url with a cors-breaking-proxy
</p>
</div>
<script type="text/javascript">
(function(){
var L=self.location.href,L2,q=L.indexOf("?");

if(q+1){
 L2=L.substr(0,q);

 var e=L.substr(q+1).split("&"),i=e.length,c,c2,f;
 while(i--){ c=e[i]; c2=c.indexOf("="); if(c.substr(0,c2).toLowerCase()=="jsl") f=decodeURIComponent(c.substr(c2+1));
  if(f){ var jse=document.createElement("script");
   jse.onerror=function(){ //in case of mime type checking
     var ft=f.split("/"); if(!((ft[0]=="http"||ft[0]=="https")&&ft[1]=="")) return 0;
     var xhr=new XMLHttpRequest();
     xhr.open("GET",f,!0);
     xhr.responseType="text"; xhr.onload=function(){  jse=document.createElement("script");  jse.innerHTML=xhr.response.replace(/\<\/script\>/g,"<\\/script>"); document.body.appendChild(jse); };
     xhr.send();
   };
   jse.src=f; document.body.appendChild(jse);
  }
 }
}else L2=L;

 document.getElementById("haa").innerText=L2;
})();
</script>
</body>
</html>