This website is using a significant amount of memory

Is there anyway to fix this freaking problem? "This website is using a significant amount of memory" This mac has done this from the second it went out of warranty and now its doing it in the middle of my online classes and keeps rebooting Safari. You would think paying as much as these things cost this wouldn't be an issue. Oh, and my $2700 MacBook Pro I bought a year ago already needs a new battery. I have nearly $5500 in computers and both are freaking paper weights. I had to dig out my son's 7 year old school HP laptop covered with freaking stickers to finish my class today.