Essayez-le vous-même - CSS Reference js

<!DOCTYPE html>
<html>
<body>

<p>Click the "Try it" button to set the font-size-adjust property of the second DIV element to "0.58", which is the aspect value of the font used in the first DIV element (Verdana):</p>

<button onclick="myFunction()">Try it</button>

<div style="font-family:verdana">
  <p>You control the font size better with the font-size-adjust property.</p>
</div>

<div id="myDIV">
  <p>You control the font size better with the font-size-adjust property.</p>
</div>

<script>
function myFunction() {
   document.getElementById("myDIV").style.fontSizeAdjust = "0.58";
}
</script>

<p><b>Note:</b> The font-size-adjust property is only supported in Firefox.</p>

</body>
</html>