codice:
<html>
<head>
<script>
	function go() {
		qs = location.search.substr(1);
		param = qs.substr(qs.indexOf("=")+1);
		selectFld = document.frm.sel.options;
		for (i=0; i<selectFld.length; i++) {
		if (selectFld[i].value == param)
			selectFld[i].selected = true;
		}
	}
</script>
</head>
<body onLoad="go()">
<form name="frm">
<select name="sel">
	<option value="a">a</option>
	<option value="e">e</option>
	<option value="i">i</option>
</select>
</form>
<form>
	<input type="text" name="param">
	<input type="submit">
</form>
</body>
</html>