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

Ensures that the object is displayed (or should be) only to readers and similar devices. It give more sense in context with other element with attribute aria-hidden="true".

  
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Glyphicon will be displayed on all other devices, word Error: on text readers.