Tryit Editor v2.9

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

<embed id="myEmbed" src="helloworld.swf" width="200" height="200" style="border:1px solid">

<p>Click the button to change the width of the flash animation to 500 pixels.</p>

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

<script>
function myFunction() {
    document.getElementById("myEmbed").width = "500";
}
</script>

</body>
</html>