<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "[URL unfurl="true"]http://www.w3.org/TR/html4/strict.dtd">[/URL]
<html>
<head>
<title>Enabling Certain Amount of Checkboxes</title>
<script language="javascript" type="text/javascript">
<!--
var totalCBs = 0;
var maxChecked = 3;
function keepTrack(c) {
totalCBs += c.checked ? 1 : -1;
enableDisable( c.form, totalCBs == maxChecked );
}
function enableDisable(f, b) {
var e = f.elements;
for (var i = 0; i < e.length; i++) {
if (e[i].type == 'checkbox' && !e[i].checked) e[i].disabled = b;
}
}
-->
</script>
<style type="text/css">
</style>
</head>
<body>
<form name="f">
<input type="checkbox" name="cb1" onclick="keepTrack(this);" /> Checkbox 1<br />
<input type="checkbox" name="cb2" onclick="keepTrack(this);" /> Checkbox 2<br />
<input type="checkbox" name="cb3" onclick="keepTrack(this);" /> Checkbox 3<br />
<input type="checkbox" name="cb4" onclick="keepTrack(this);" /> Checkbox 4<br />
<input type="checkbox" name="cb5" onclick="keepTrack(this);" /> Checkbox 5<br />
<input type="checkbox" name="cb6" onclick="keepTrack(this);" /> Checkbox 6<br />
<input type="checkbox" name="cb7" onclick="keepTrack(this);" /> Checkbox 7<br />
</form>
</body>
</html>