The fontSize property is used to set or get the font size of characters in a word should appear.
Syntax:
- It returns the fontSize property.
object.style.fontSize
- It sets the fontSize Property.
object.style.fontSize = "value|initial|inherit"
Property Values:
| Value | Description |
|---|---|
| xx-small x-small small medium large x-large xx-large | Predefine sizes of font |
| smaller | Decreases by one relative unit of the font-size |
| larger | Increases by one relative unit of the font-size |
| length | Font-size in length unit |
| % | % of the parent element's font size |
| initial | Set default value |
| inherit | Inherit property from its parent value |
Return value: It returns the font size of the text of element.
Example-1: Change font size into small.
<!DOCTYPE html>
<html>
<head>
<title>DOM Style fontSize Property </title>
</head>
<body>
<center>
<p style="color: green;
width: 100%;
font-size: 30px;
font-weight: bold;"
id="Geek1">
GeeksForGeeks
</p>
<h2>DOM Style fontSize Property </h2>
<br>
<button type="button" onclick="myGeeks()">
Click to change
</button>
<script>
function myGeeks() {
// Change font size in to small.
document.getElementById(
"Geek1").style.fontSize = "small";
}
</script>
</center>
</body>
</html>
Output:
- Before click on button:

- After click on button:

Example-2: Change font-size into xx-large.
<!DOCTYPE html>
<html>
<head>
<title>DOM Style fontSize Property </title>
</head>
<body>
<center>
<p style="color: green;
width: 100%;
font-size: 10px;
font-weight: bold;"
id="Geek1">
GeeksForGeeks
</p>
<h2>DOM Style fontSize Property </h2>
<br>
<button type="button" onclick="myGeeks()">
Click to change
</button>
<script>
function myGeeks() {
// change into xx-large.
document.getElementById(
"Geek1").style.fontSize = "xx-large";
}
</script>
</center>
</body>
</html>
Output:
- Before click on button:

- After click on button:

Example-3: Change font-size using length unit.
<!DOCTYPE html>
<html>
<head>
<title>DOM Style fontSize Property </title>
</head>
<body>
<center>
<p style="color: green;
width: 100%;
font-size: 10px;
font-weight: bold;"
id="Geek1">
GeeksForGeeks
</p>
<h2>DOM Style fontSize Property </h2>
<br>
<button type="button" onclick="myGeeks()">
Click to change
</button>
<script>
function myGeeks() {
// Change font size from
// from 10px to 30px
document.getElementById(
"Geek1").style.fontSize = "30px";
}
</script>
</center>
</body>
</html>
Output:
- Before click on button:

- After click on button:

Example-4: Change font-size using '%'
<!DOCTYPE html>
<html>
<head>
<title>DOM Style fontSize Property </title>
</head>
<body>
<center>
<p style="color: green;
width: 100%;
font-size: 10px;
font-weight: bold;"
id="Geek1">
GeeksForGeeks
</p>
<h2>DOM Style fontSize Property </h2>
<br>
<button type="button" onclick="myGeeks()">
Click to change
</button>
<script>
function myGeeks() {
// Change font-size from 100% to 200%
document.getElementById(
"Geek1").style.fontSize = "200%";
}
</script>
</center>
</body>
</html>
Output:
- Before click on button

- After click on button

Supported Browsers: The browser supported by HTML | DOM Style fontSize Property are listed below:
- Google Chrome 1
- Edge 12
- Internet Explorer 5.5
- Mozilla firefox 1
- Opera 7
- Safari 1