auto fill form from web page content

I need to fill a field in a PDF form (version 8 or newer) with a value provided by a web page.  The webpage is a counter to provide a unique, sequetial number.

I have been able to do this with Get() when using FormCalc, however I need more logic control than is provided in FormCalc.

I have attempted to implement the logic with JavaScript and getURL. When I open the form the JavaScript Console indicates: "TypeError: xfa.host.getURL is not a function"

Here is my code with some console diagnostics included:

console.println("formEmailed = " + xfa.form.topmostSubform.formEmailed.value);

if( xfa.form.topmostSubform.formEmailed.value == 1) {

  console.println("assignedTR = " + xfa.form.topmostSubform.assignedTR.value);

  if( !xfa.form.topmostSubform.assignedTR.value == 0){

    console.println("Getting URL...");

    xfa.host.getURL("http://somehost.com/index.html", true); //Get( "http://somehost.com/index.html");

    console.println("Field value = " + this.rawValue);

   // Verify a value actually got assigned

    if( this.rawValue.length > 0)

      xfa.form.topmostSubform.assignedTR.value = 1;

  } else {

    console.println("Not getting URL");

  }

}

Note: formEmailed and assignedTR are global variables.  The code is associated with the DocReady event.

I have been unable to locate any examples of filling a field in a from from a webpage.

Ultimately, I want the value from the webpage assigned to this.rawValue so that the value becomes part of the data in the form.

Suggestions?