AJAX :: Script Causing Automatic Page Reload?

I'm writing a script, part of which calls an AJAX request to populate a table. This script runs when the page is first loaded and when different buttons are clicked on the page (I won't go into the details here). It works just fine when the page is first loaded, but whenever the function is called from any other event on the page (onclick, etc) it performs the function, but then proceeds to reload the whole page!

I've spent a long time debugging and trying to figure out exactly where the trouble is starting, and the only thing I can think is that some sort of "reload page" command is being sent to the browser somewhere that I'm not seeing. In Firefox, after the request is complete and the response data is written to the page, the page reloads. However, in Safari, the page reloads after the readyState is 1, so the request hasn't even been sent yet.

Here is the offending function:

Javascript Code:

function fillLogTable(date, org, poc, name)
{
document.getElementById("visitLogTableDiv").innerHTML = "<br />Loading...";
//fetch the logs

[Code]....