Firefox gets stuck in broken script loop

I like Firefox but several years ago had to switch to Chrome as a primary browser because FF will consume every ounce of ram and CPU my machine has and run almost infinitely crushing the machine. This happens on both Linux and Mac and has been going on for years. I typically have 2 to 5 windows, each window having 2 to 15 tabs open. Unfortunately I have to have flash enabled for many tasks. I tend to run with as few add ons as I can, but typically have several and the behavior has happened with no add ons outside defaults and Flash. I generally only close my browser when I reboot and only reboot when kernel updates occur. The problem can only be resolved by closing down Firefox, but usually it gets so bad so quickly that I have to hard boot. I cannot even jump to a term window to kill FF. I once left the machine up for 17 hours stuck in the script is not responding loop and it was still unresponsive. Sometimes the machine will come back long enough to kill FF after several minutes, but usually once I start getting the script unresponsive pop ups, I cannot even close them. They just pile up and the machine collapses. It takes a LOT to crater a Mac or Linux box. FF is the ONLY app I've seen do it. I've been using Linux for over 20 years, Macs for about 7 now. If I do not use FF my machine never freezes. If I do use FF and do not close it down within 10-12 hours it will clobber my machine. So the problem is definitely FF. I have not tried disabling Flash as I cannot do without Flash right now as much as I hate Flash and wish it'd go away. There are too many sites that I need which use Flash. Nor am I about to start closing apps up. That would reduce me to Windows like levels of functionality and time consumption per task. Simply not acceptable. I'd rather chew my arm off with Bill Gate's dentures than to single task. It would be nice if FF freed up memory when you closed a tab or window. I close a Chrome, Safari or Opera tab or window and memory is freed. I close a FF tab or window nothing is freed. I spawn a single instance of FF normally. On rare occasions another app will spawn a FF window. I then use new tab or window function to create new tabs & windows. Sites that typically give me the greatest issues are forum sites, sites that use a lot of flash, graphically intense sites, music sites and similar sites. www.mlb.com for example is brutal and very likely to trigger the script errors. Especially if I have 4 or 5 tabs open with mlb.com links. FF stays updated with auto update. I do not visit porn sites, shareware sites, or other sites likely to contain malicious software or malware. Two sites that are always open 24/7 are gmail and yahoo mail. I also typically have several Google search windows open at any given time. Sorry Yahoo's search is biased and inferior and I won't use Microsoft anything under ANY circumstances. So it's Google or nothing at the moment in terms of search engines. I'd love to have an alternate to support. Since the problem happens on multiple OS's, the only common plug in beyond default is Flash I've omitted OS specifics. I use KDE as my window manager typically on Linux. Default Mac OSX window manager on Mac. The problem started 5 to 9 years ago. Prior to that I could have an almost infinite number of tabs open almost infinitely and if I did run out of mem I could easily get to a term window and kill FF. I think it was about 6 or 7 years ago that I started experiencing this and was forced over to Chrome as my primary browser. That's about all I can think of. Wandered in here looking for locations on FF profile info to port my FF to a new Mac and got a survey asking how FF was doing. The machine crushing crash is my only major complaint, though it's a deal killer. I only use FF sparingly for tasks and make sure to close it down in hours after opening it to keep it from killing my machine. Figured I'd mention the issue.