Question

如果在本地（而不是从Web服务器）加载包含Javascript代码的.htm文件，如何使用Javascript检查本地磁盘上是否存在.htm文件？

Answer 1

此解决方案适用于IE和FF的大多数版本。从本地磁盘运行时，无法在Chrome上运行。

我在同步模式下使用XHR和旧的IE ActiveX控件。您可以轻松地将其转换为使用onreadystatechange回调运行异步。

在您自己的Javascript代码中，只需调用IsDocumentAvailable（“otherfile.htm”）即可设置。

    function IsDocumentAvailable(url) {

        var fSuccess = false;
        var client = null;

        // XHR is supported by most browsers.
        // IE 9 supports it (maybe IE8 and earlier) off webserver
        // IE running pages off of disk disallows XHR unless security zones are set appropriately. Throws a security exception.
        // Workaround is to use old ActiveX control on IE (especially for older versions of IE that don't support XHR)

        // FireFox 4 supports XHR (and likely v3 as well) on web and from local disk

        // Works on Chrome, but Chrome doesn't seem to allow XHR from local disk. (Throws a security exception) No workaround known.

        try {
            client = new XMLHttpRequest();
            client.open("GET", url, false);
            client.send();
        }
        catch (err) {
            client = null;
        }

        // Try the ActiveX control if available
        if (client === null) {
            try {
                client = new ActiveXObject("Microsoft.XMLHTTP");
                client.open("GET", url, false);
                client.send();
            }
            catch (err) {
                // Giving up, nothing we can do
                client = null;
            }
        }

        fSuccess = Boolean(client && client.responseText);

        return fSuccess;
    }

Answer 2

这篇文章可能有所帮助：http://www.c-point.com/JavaScript/articles/file_access_with_JavaScript.htm

并且：Local file access with javascript

Answer 3

假设htm文件位于同一个域中，您可以执行以下操作：

function UrlExists(url) {
  var http = new XMLHttpRequest();
  http.open('HEAD', url, false);
  http.send();
  return http.status!=404;
}

由于域安全限制，这在多个浏览器（例如Chrome）上的本地文件系统上无效。

使用Javascript检查本地磁盘上是否存在.htm文件

3 个答案: