Can't show web server (mongoose) generated HTML

Question

I'm new to web development. I'm embedding mongoose web sever in my application. What I want to do is from a browser, I connect to mongoose. Then, when the user let say enter some data and click a button, it will ask mongoose to generate an html which is loaded to a frame.

Mongoose generated the html correctly. The file exist but I keep getting "Error 404: Not Found File not found" on the frame.

My code looks like this:

I have javascript function showListView()

function showListView(doc1)
{
 parent.listViewFrame.location.href=doc1;
}

The above function is executed when user click button. See below how I define it:

onclick="showListView('http://localhost:8080/ListView/some.html')"

The javascript code is implemented in the main html (which also contains other form UI, such as button)

The code on mongoose looks like:

if (strcmp(request_info->uri, "/ListView/some.html") == 0)
{
  // Generate some.html here.
  return "";
}

The html file is generated correctly. It exists in the correct path. But I keep getting "Error 404: Not Found File not found" on the frame. If I reload frame content, then I see some.html displayed correctly.

What did I do wrong? Can someone please help me? I want "some.html" displayed immediately after I click the button without having to reload frame content. Many thanks before.