Closure Compiler Warning `dangerous use of the global this object`?

Question

Dear folks, Closure Compiler gives this warnings in Advanced Mode, underlining {this.

JSC_USED_GLOBAL_THIS: dangerous use of the global this object at l

Answer 1

"this" might have different meaning in different context, so it tells you exactly that. You can use closures instead:

Instead of

hovers[i4].onfocus = function() {this.className += "Hovered";}

have:

hovers[i4].onfocus = function(self) 
{
    return function() {self.className += "Hovered";}
}(hovers[i4])