JavaScript Tutorial/Style/setProperty
Set style by property name
<html>
<head>
<title>Style Example</title>
</head>
<body>
<div id="div1"
style="background-color: red; height: 50px; width: 50px"
onmouseover="this.style.setProperty("background-color", "blue", "")"
onmouseout="this.style.setProperty("background-color", "red", "")"></div>
</body>
</html>