Chrome userscripts: Why does it execute twice?

[Ichinisan]

This userscript helps my productivity by selecting a filter option automatically on a web system we use a *lot* at work.

// ==UserScript==
// @match http://blah/blah/*/blahsearch.do
// ==/UserScript==

document.getElementById("status").value="1";

It works. However, I noticed something strange about the way Chrome processes userscripts (?).

While developing the userscript, It was tricky to set up the filter because the web page hides the appropriate URL for that section of the page. To work out the filter and make sure my script was activating, I added an alert box message.

// ==UserScript==
// @match http://blah/blah/*/blahsearch.do
// ==/UserScript==

alert("userscript active");
document.getElementById("status").value="1";

The filter works, but I get TWO alert messages when it matches the page. Is that normal? I'm guessing it might have something to do with the site / system I'm accessing because it has always been a little glitchy and strange.

 

[Sgraffite]

Is there an iframe on the page, or some other resource request that also matches the @match?

 

[Ichinisan]

Is there an iframe on the page, or some other resource request that also matches the @match?

I'll have to check it again tomorrow.