JavaScript获取本地文件扩展名示例

<html>
<head>
<title>取得文件字段中选取文件的扩展名</title>
<script language="javascript">
<!--
 function getFilename(){
  str = new Array();
  filename = form1.file.value;
  str = filename.split(".");
  extname = str[str.length - 1];
  alert(extname);
 }
//-->
</script>
</head>
<body>
<form enctype="multipart/form-data" name="form1">
 <input type="file" name="file">
 <input type="button" value="显示扩展名" onClick="getFilename()">
</form>
</body>
</html>