Tryit Editor v2.9

Edit This Code:
<!DOCTYPE html>
<html>
<body>

<object id="myObject" width="250" height="200" data="helloworld.swf" style="border:1px solid black"></object>

<p>Click the button to change the width of the object element to 400px.</p>

<button onclick="myFunction()">Try it</button>

<p id="demo"></p>

<script>
function myFunction() {
    document.getElementById("myObject").width = "400";
}
</script>

</body>
</html>