Go to URL after OK button if alert is pressed

What do you mean by "make sure"?

alert('message');
window.location = '/some/url';

redirects user after they click OK in the alert window.

I suspect you mean in a confirm window (ie. Yes/No options).

if (window.confirm('Really go to another page?'))
{
    // They clicked Yes
}
else
{
    // They clicked no
}