My test.html file:
<html>
<head>
<title> my title </title>
<script> type="text/javascript" src="/openflashchart/js/swfobject.js"</script>
</head>
<body>
<tr>
<td>
<script type="text/javascript">
swfobject.embedSWF("/openflashchart/open-flash-chart.swf","my_chart","480","360","9.0.0","expressInstall.swf",{"data-file":"data.json"});
</script>
<div id="my_chart"></div>
</td>
</tr>
...blabla
</body>
</html>
I place openflashchart in the home directory of apache, i.e., /Library/WebServer/Documents/. This html file and the json data to be loaded are placed in Documents/Data/myfiles. This page is supposed to be displayed with a curve. However, there is nothing as I visit http://localhost/Data/myfiles/test.html.
Update
Now I know that the reason is that I didn't install Adobe Flash Player, while this package is flash based. Untill now I cannot successfully install Adobe Flash Player on my mac. But that's another problem.
Since chrome has built-in support for flash, this page can be displayed properly with it. I still has probelms with safari and firefox.