After calling chrome.tabs.query, the results are not available

I'm creating (learning) an extension for Google Chrome.

To debug some code, I inserted console.log(), as follows:

var fourmTabs = new Array();
chrome.tabs.query({}, function (tabs) {
    for (var i = 0; i < tabs.length; i++) {
        fourmTabs[i] = tabs[i];
    }
});
for (var i = 0; i < fourmTabs.length; i++) {
    if (fourmTabs[i] != null)
        window.console.log(fourmTabs[i].url);
    else {
        window.console.log("??" + i);
    }
}

It's very simple code: get all tabs info into an array of my own, and print some things.

To check whether the code works as it should, I run the code. Here comes the problem:

• When I use breakpoints (via the Developer tools), the code runs fine.
• Without breakpoints, nothing is printed.

Any idea why?