Web, including JavaScript, should work fine on that laptop.
Until recently, my daily driver was the T500 (the larger screen version of the T400 in the article), and it worked fine for everything except GPU.
(I actually downgraded to the T500 years ago, because I was pissed off about the Intel Management Engine.)
Recently, I upgraded from the T500 to the T520, which is the last ThinkPad with a non-chiclet keyboard. It works fine for everything except GPU and fitting inside many backpacks.
With ThinkPads of this era, you want to get a high-spec variant of the model (e.g., top-res IPS display), and then make the following upgrades:
* SSD
* run Linux
* run uBlock Origin (and block most of the third-party surveillance, which hurts performance) (JS runs fine, so long as you're not running multiple dueling adtech slimeballs' intimate mouse trackers)
* max out the RAM (you don't need that much for Linux, unless you're using an exceptionally bloated desktop option, but it's cheap, and you can use it to keep filesystems like ~/.cache off your SSD )
* (optional) replace the CPU with a more optimal one for power draw or heat, or maybe for compute (these are socketed in most models)
* (optional, not for the faint of heart) install Coreboot, and then you have more WiFi upgrade options
I'm sure window.open will work great, absolutely. HN will probably work wonders, too. nbcnews? new (arg) reddit?
We could go back a little more and find a great PII 400. I had one with a CL 3Dfx Voodoo2 12MB, though I forget the 2D card.
It played MP3s REALLY well! As long as that is all you wanted to do because anything else would introduce skips and pops.
I like old machines, but I would hardly call them day-to-day usable with modern apps, and I would question the underlying hardware/firmware security the rest of the way.
Not sure about the T520 but my T420 has an old dedicated Nvidia graphics (quadro NVS 4200m). Still seems to handle anything browser related great and I suspect this is the reason (integrated GPU in the dual core i5 probably sucks). They're rarer and harder to find though
You can use the T420/T520's keyboard in a T430/T530 with modifications to the firmware, some plastic around the keyboard part itself, and the ribbon cable (just pin isolation with tape). It lets you go with Ivy Bridge over Sandy Bridge.
I have a T430 with the T420's keyboard and it lasted me 7 years of daily use before battery life became too big of an issue for me (even with a single DDR3L RAM module and a slice battery), so I put it aside. The typing experience was really excellent.
Upgrading the CPU to a quad-core model (ideally one that consumes 35W over 45W) is one of the best upgrades to make for anyone still using these machines.