<!DOCTYPE html>
<html>
<body>
<p id="p1">
This is a text.
This is a text.
This is a text.
This is a text.
</p>
<input type="button" value="Hide text" onclick="document.getElementById('p1').style.visibility='hidden'">
<input type="button" value="Show text" onclick="document.getElementById('p1').style.visibility='visible'">
</body>
</html>