How to unset a JavaScript variable?

Question

I have a global variable in JavaScript (actually a window property, but I don\'t think it matters) which was already populated by a previous script but I don\'t

Answer 1

Variables, in contrast with simple properties, have attribute [[Configurable]], meaning impossibility to remove a variable via the delete operator. However there is one execution context on which this rule does not affect. It is the eval context: there [[Configurable]] attribute is not set for variables.