javascript string.lastIndexOf does not work with span innerHTML

Answer 1

No, it has nothing to do with innerHTML. In the call to lastIndexOf, the » entity is not expanded as it is in the HTML code; instead it is considered as a raw string. Replace it with the actual character and it will work:

var index = str.lastIndexOf("»");

Answer 2

If you use innerHTML, you have to use "»" instead of "»".