What is sr-only in Bootstrap 3?

Question

What is the class sr-only used for? Is it important or can I remove it? Works fine without.

Here\'s my example:

Answer 1

I found this in the navbar example, and simplified it.

  
Default
  
Static top
  
Fixed top (current)

You see which one is selected (sr-only part is hidden):

• Default
• Static top
• Fixed top

You hear which one is selected if you use screen reader:

• Default
• Static top
• Fixed top (current)

As a result of this technique blind people supposed to navigate easier on your website.