Possible to open a URL in a browser without creating new tabs?

I frequently want to perform this pattern:

while someEvent():
    loadIntoDesktopBrowser( url )

However if I simply supply the url to chrome, firefox or xdg-open, then the url is always opened and I quickly end up with many open tabs (eventually requiring that I restart the browser). Is there a browser with a command-line option to let me either:

• limit the number of tabs to 1


• if the URI is already opened in a tab, reload that url (or load the url in a new tab if it is not already open)