给出以下示例
<img id="my_img" src="images/current.png" />
<script language="javascript">
var i = document.getElementById('my_img');
var filetime = i.is_there_any_method_for_this(); // ?????
i.title = 'image created: ' + filetime; // don't care about formating now
</script>
我想询问是否is_there_any_method_for_this();存在或者是否可以访问所显示图像的文件创建(或修改)时间.