Is a chunk of HTML and javascript that crashes IE rare? Unless my memory is faulty, I feel like we've come across code that crashes various IE versions a dozen

Is a chunk of HTML and javascript that crashes IE rare? Unless my memory is faulty, I feel like we've come across code that crashes various IE versions a dozen times in the last few years. Reporting these bugs to Microsoft is practically unimaginable to me -- I wouldn't know where to start.