Ahí va otra forma, que la primera parece que a NS no le gusta
Código PHP:
<script language="JavaScript">
var miVariable
Valor = unescape(document.location.search.substr(1))
if(Valor != "")
{
Valor = Valor.split("&")
for(m=0;m<Valor.length;m++)
{
Valor2 = Valor[m].split("=")
if(Valor2[0] == "miVariable")
{
miVariable = Valor2[1]
}
}
}
if(miVariable != null) {alert(miVariable)}
</script>
</head>
<body>
<form name="form1" method="get" action="#" >
<input type="text" name="miVariable">
<input type="submit" name="Submit" value="Botón" onclick="">
</form>
