Reakce na odpověď

Ak to nechceš robiť na serveri, tak si to môžeš uložiť napr. do localStorage.

Príklad:

<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8" />
</head>
<body>
	<form method="post">
		<div>
			Otevřený text:
			<br />
			<textarea name="OT" cols="40" rows="3">
				<msp:evaluate>MSPValue[ $OT, "Pes"]</msp:evaluate>
			</textarea>
		</div>
		<div>
			<input type="radio" name="rad" value="man" />
			Vlastní klíč
			<br />
			<input type="radio" name="rad" value="gen" />
			Generovaný klíč
		</div>
		<div>
			<br />
			Klíč:
			<br />
			<textarea name="key" id="klic" cols="40" rows="3">
				<msp:evaluate>MSPValue[ $key, "101"]</msp:evaluate>
			</textarea>
		</div>
		<div>
			<input type="submit" value="Šifrovat" />
		</div>
	</form>
	<script>
var form = document.forms[0];
var selected = localStorage.selectedRadio;
for (var i = 0, n = form.rad.length; i < n; ++i) {
	var r = form.rad[i];
	r.onclick = function() {
		localStorage.selectedRadio = this.value;
		var klic = document.getElementById('klic');
		klic.disabled = this.value == 'gen';
	}
	if (selected == r.value) {
		r.checked = true;
		r.onclick();
	}
}
	</script>
</body>
</html>

JavaScript - radio button