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 console: Expected ')'

In Chrome it gives this error in the console: Uncaught SyntaxError: Unexpected token =

Both browsers mark the source of the error as the function creation line.

Answer 1

You can't do this, but you can instead do something like:

function saveItem(andClose) {    if(andClose === undefined) {       andClose = false;    } } 

This is often shortened to something like:

function setName(name) {   name = name || 'Bob'; } 

Update

The above is true for ECMAScript <= 5. ES6 has proposed Default parameters. So the above could instead read:

function setName(name = 'Bob') {} 

Answer 2

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.