I am trying on Firefox,IE 9,Chrome and Opera the code below ,but the onInitFs(fs) function doesn't get called.if I add '()' to onInitFs in the window.requestFileSystem(window.PERSISTENT, 1024\*1024, onInitFs, errorHandler) that function get called but fs is null ?
Does anybody know how to solve this problem?I try on windows 7.I'll appreciate very much your help.

```
<!DOCTYPE HTML>
`<html>
    <head>  
    <script>
        function errorHandler(e){
            alert("errorrrr");
        }
        function onInitFs(fs){
        alert("onInitFs");
        }
        function readClick(){
                 if (window.webkitRequestFileSystem) {
                     window.webkitRequestFileSystem(window.PERSISTENT, 1024*1024,onInitFs,errorHandler);
                } 
                 else {
                    window.requestFileSystem(window.PERSISTENT, 1024*1024, onInitFs, errorHandler);
                }

            alert("read finishsssss");
        }
        </script>
    </head>
<body>
<input type="button" value="Read dir" onclick="readClick()">
    <ul id="filelist"></ul>
</body>
</html>

```