So in javascript we have a onerror handler which is also on the window object, this means if we assign a function to onerror we can call it by generating a javascript error! How do we generate a javascript error? Throw is a nice way, this means throw can pass an argument to a function you can create some pretty awesome crazy looking javascript.


onerror=alert;throw 1;

This works on every browser apart from Firefox *, Safari and IE will just call the function with the argument but Chrome and Opera add uncaught to the argument. This is no big deal though since we can just modify it slightly and use a different object as an argument such as a string.


onerror=eval;throw'=alert\x281\x29';