will this snippet leak? I have some assumptions:
1. in old browsers, there can only be one page in each browser window. so in old browsers, closing the browser window will clear the leak. but in newer browsers where one browser window can accommodate multiple tabs which means that one browser window can accommodate multiple pages at once, closing the one tab containing the snippet above is enough to solve the leak. so in newer browsers, no need to close other tabs that don't contain the snippet right? just the one containing the snippet is enough to "plug" the leak.
2. if I change the code to this: