You can try to run the following code to learn how to work with the <polygon> tag in HTML5:
<html>
<head>
<style>
#svgelem{
position: relative;
left: 50%;
-webkit-transform: translateX(-40%);
-ms-transform: translateX(-40%);
transform: translateX(-40%);
}
</style>
<title>SVG</title>
<meta charset="utf-8" />
</head>
<body>
<h2 align="center">HTML5 SVG Star</h2>
<svg id="svgelem" height="200" xmlns="https://www.w3.org/2000/svg">
<polygon points="100,10 40,180 190,60 10,60 160,180" fill="red"/>
</svg>
</body>
</html>