Uncaught IndexSizeError: Failed to execute 'getRangeAt' on 'Selection': 0 is not a valid index

Question

What is problem here?

if ( window.getSelection() ) 
  EditField = window.getSelection().getRangeAt(0);

throws error:

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Answer 1

The exact way to address this problem (like 90% of everything in JavaScript) is object detection; selection related isn't as straight forward of course:

if (window.getSelection().rangeCount >= 1) {var r = window.getSelection().getRangeAt(0);}

To test throw window.getSelection().rangeCount in to a console when there is no selected text and it'll return 0; with a selection it'll return 1. I am not sure however if and how you could manage to get it to return 2 or greater.