I am new to HTML and learning it from w3schools. I am looking at object tag and trying to display a pdf in a browser. I am unable to understand why the height attribute doesn't work in below code
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8"/>
<title>try here</title>
</head>
<body>
<object data="redBus_Ticket_25718916.pdf" type="application/pdf" height="100%" width="100%">sample</object>
</body>
</html>
I am expecting the entire page to be a PDF document. but what I see is,

Can some one tell me reason for such behavior ?
Interestingly when I remove the definition, it works as expected. Don't know how they are related.Please help me in understanding the behavior.