<!DOCTYPE html>
<html lang="en-US">
<head>
<style>
#outerDiv{
display: grid;
grid-template-columns: auto auto auto;
grid-template-rows: auto auto;
grid-auto-flow:row;
border: 1px solid black;
grid-auto-flow: row;
}
#outerDiv div{
border: 1px solid #00f;
background-color: rgba(0,0,255,.2);
padding: 25px;
margin: 8px;
text-align: center;
}
#outerDiv div:nth-child(3){
grid-column-end: span 2;
}
</style>
</head>
<body>
<h1>CSS grid-auto-flow Property</h1>
<div id="outerDiv">
<div>Div 1</div>
<div>Div 2</div>
<div>Div 3</div>
<div>Div 4</div>
<div>Div 5</div>
<div>Div 6</div>
<div>Div 7</div>
</div>
<button onclick="myFunction()">Click Me</button>
<script>
var x = document.getElementById("outerDiv");
function myFunction(){
x.style.gridAutoFlow = "dense";
}
</script>
<p><strong>Note</strong>: Click on the button to change the css property 'grid-auto-flow' from row to dense.</p> </body>
</html>