Use the fontSizeAdjust property to preserve the readability of text. It sets the aspect value of a font i.e. the difference between the size of lowercase and uppercase letters.
Example
You can try to run the following code to preserve the readability of text when font fallback occurs with JavaScript −
<!DOCTYPE html>
<html>
<body>
<h1>Heading 1</h1>
<p id="myID">
This is Demo Text.
</p>
<button type="button" onclick="display()">Set Aspect Value</button>
<script>
function display() {
document.getElementById("myID").style.fontFamily = "verdana,sans-serif";
document.getElementById("myP").style.fontSizeAdjust = "0.90";
}
</script>
</body>
</html>