Question

I am trying to find out whether or not a file exists, before trying to download it. The file is a ClickOnce application.

I have already tried the following code, but this does not work (maybe because the URL is on a different server and domain?);

$.ajax({
    url: 'http://www.example.com/somefile.ext',
    type: 'HEAD',
    error: function()
    {
        //File does not exist
    },
    success: function()
    {
        // File exists
    }
});

Is there another solution, or is there a means to get this one to work?

Answer 1

Yes, this should not work if the URL is on a different server. If you want to make this work, you will need control over the server where the URL is downloaded from. If so, you should set
the Access-Control-Allow-Origin header to the name of the server from which your JavaScript is loaded.

See Stack Overflow question jQuery AJAX cross domain for more details.