<html>
<head>
</head>
<body>
<div>
<span if="foo">Message A</span>
<span if="foo[0]">Message B</span>
<span if="foo[1]">Message C</span>
<span if="foo[3]">Message D</span>
<span if="!foo[3]">Message E</span>
</div>
</body>
</html>