I'm experiencing a constant problem involving a script while using Firefox browser, with Facebook open.

A pop up window on the page advises me that the following script is causing the problem....


...and gives me a choice to "Cancel, Debug, or Continue" ??

I don't understand the nature of Scripts and am therefore at a complete loss, and confused about how to deal to the problem to sort it out.

Firefox becomes very sluggish, unresponsive and freezes when this annoying event happens.

A guess suggests that Java Script is associated with it.