Probá con algo así:
Código PHP:
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>test</title>
<script>
function rpc(url){
oldsc=document.getElementById("old_sc");
if(oldsc)
document.getElementsByTagName('body')[0].removeChild(oldsc);
sc=document.createElement('img');
sc.style.display='none';
sc.id="old_sc";
sc.src=url+'&'+Math.random();
document.getElementsByTagName('body')[0].appendChild(sc);
}
</script>
</head>
<body>
<a href="javascript:rpc('test.asp?')">conectar</a>
</body>
</html>