<html>
<header>
<script src="prototype.js"></script>
</header>
<body>
<input type="checkbox" id="che1" name="che" /> 1 <br />
<input type="checkbox" id="che2" name="che" /> 2 <br />
<input type="checkbox" id="che3" name="che" /> 3 <br />
<input type="checkbox" id="che4" name="che" /> 4 <br />
<input type="checkbox" id="che5" name="che" /> 5 <br />
<input type="button" value="Marcar" onclick="fnMarcar(true);" /> <br />
<input type="button" value="Desmarcar" onclick="fnMarcar(false);" /> <br />
<script type="text/javascript">
function fnMarcar(tipo){
$$('input').each(function(e){
if(e.type == 'checkbox' && e.name == 'che'){
e.checked = tipo;
}
});
}
</script>
</body>
</html>
