Set the columnSpan property to all, if you want the columns to span across in JavaScript. You can try to run the following code to return how many columns an element should span across with JavaScript −
Example
<!DOCTYPE html>
<html>
<head>
<style>
#myID {
column-count: 4;
}
</style>
</head>
<body>
<p>Note- The columnSpan property won't work in Firefox.</p>
<button onclick = "display()">Span Columns</button>
<div id = "myID">
<h1 id = "h1ID">Heading Level 1 for Demo</h1>
This is Demo Text. This is Demo Text. This is Demo Text. This is Demo Text.
This is Demo Text. This is Demo Text. This is Demo Text. This is Demo Text.
This is Demo Text. This is Demo Text. This is Demo Text. This is Demo Text.
This is Demo Text. This is Demo Text. This is Demo Text. This is Demo Text.
This is Demo Text. This is Demo Text. This is Demo Text. This is Demo Text.
</div>
<script>
function display() {
document.getElementById("h1ID").style.columnSpan = "all";
}
</script>
</body>
</html>