Question

I override a number of methods on the Element prototype so I can add in a custom hook like so:

Element.prototype._method = Element.prototype.method;
Element.prototype.method = function(){
  this._method.apply(this, arguments);
  // custom callback
}

At some point, I want to restore the original method, so I do:

Element.prototype.method = Element.prototype._method;

However, when the method element is called on a node, it seems to throw a Invalid procedure call or argument error in IE8. Am I restoring the original method incorrectly?

Answer 1

It seems IE8 has this issue and is not quite easy to resolve, but you could try delete on Element.prototype to restore an overwritten.

var old = Element.prototype.getElementsByTagName;
Element.prototype.getElementsByTagName = old;
// alert(document.body.getElementsByTagName('script').length); // this throws Error
delete Element.prototype.getElementsByTagName;
alert(document.body.getElementsByTagName('script').length); // Now it works as expected