text text text
<input type="button" onclick="document.body.style.fontSize = '50%'" value = " small ">
<input type="button" onclick="document.body.style.fontSize = '100%'" value = " normal ">
<input type="button" onclick="document.body.style.fontSize = '200%'" value = " big ">
<input type="button" onclick="document.body.style.fontSize = '500%'" value = " very very big ">