I know Javascript breakpoints are possible because I used to do it all the time in my previous job using VS2010. At my new job now, VS tells me it can't set the breakpoint. Instead, I have to put debugger;
in my code and then choose another instance of VS for debugging, but I don't want to do it that way. It's much easier to set a breakpoint, attach the debugger to the dev server, and run my code.
Edit: I just thought about it and will add that I was also using Telerik's RadCodeBlock in the past. Let me look into that more and see if that's why I was able to set script breakpoints.