Javascript Functions and default parameters, not working in IE and Chrome

Question

I created a function like this:

function saveItem(andClose = false) {

}

It works fine in Firefox

In IE it gives this error on the

Answer 1

That's not a valid ECMAScript syntax, but it is a valid syntax for Mozilla's superset of features they add to their implementation of the language.

Default parameter assignment syntax is likely coming in ECMAScript 6.