Selecting text in a div programmatically using position values belong to that text

Question

I have a div and there is a text in it.I want a part of that text to be selected programmatically according position value of characters.

Answer 1

Here is a simple way to to this:

function selectTextRange(obj, start, stop) {
  var endNode, startNode = endNode = obj.firstChild

  startNode.nodeValue = startNode.nodeValue.trim();
  
  var range = document.createRange();
  range.setStart(startNode, start);
  range.setEnd(endNode, stop + 1);
  
  var sel = window.getSelection();
  sel.removeAllRanges();
  sel.addRange(range);
}

selectTextRange(document.getElementById('textdiv'), 3, 10);

  Hello world. I am a friend.

---

Text highlight:

function highlightRange(el, start, end) {
  var text = el.textContent.trim()
  el.innerHTML = text.substring(0, start) + 
    '' +
    text.substring(start, end) + 
    "" + text.substring(end);
}

highlightRange(document.getElementById("textdiv"), 3, 10)

  Hello world. I am a friend.