xdxdxd

<!DOCTYPE html>
<html>
<head>
      <meta charset="UTF-8"/>
      <title>JS Zadanie</title>
      <style>
         body {font-family: Verdana; font-size: 12px;width:100%;margin: 0 auto;margin-top:20px;}
         div {border: 1px solid black; padding: 3px; margin: 0 auto;width:70%;}
         .przyklad {background-color: yellow; font-style: italic;}
         span {color: blue}
		 .text {font-size:16px;color:blue;font-weight:700;}
		 .text2{font-size:13px;color:blue;}
         ul {margin-top: 0px}
		 #error{color:red;}
      </style>
</head>

<body>
	<div>tu cos opisz
		<input type="number" id="wysokosc" placeholder="Wysokość"><br><br>
		<input type="number" id="podstawa" placeholder="Pole podstawy"><br><br>
		tu wklej obrazek
		<input type="button" id="button" onclick ="wykonaj();" value="Oblicz"></input><br><br>
		<span id="error"></span>

	</div>

	<script>

	function wykonaj(){
		document.getElementById('error').innerHTML = "Pole ostroslupa wynosi: " + oblicz();
	}
	function oblicz(){
		var wysokosc = document.getElementById('wysokosc').value;
		var podstawa = document.getElementById('podstawa').value;

		return wysokosc * podstawa * 1/3;
	}
	</script>


</body>

</html>