Highlighted selected text hide jquery javascript

Highlighted selected text hide jquery javascript

HTML

<div>
  <p>
   four months and four days
  </p>
  <p>
   four months and four days
  </p>
  
  </div>
<button>Hide higleted text</button>

JavaScript

function getSelectionParentElement() {
    var parentEl = null, sel;
    if (window.getSelection) {
        sel = window.getSelection();
        if (sel.rangeCount) {
            parentEl = sel.getRangeAt(0).commonAncestorContainer;
            if (parentEl.nodeType != 1) {
                parentEl = parentEl.parentNode;
            }
        }
    } else if ( (sel = document.selection) && sel.type != "Control") {
        parentEl = sel.createRange().parentElement();
    }
    return parentEl;
}
function getSelectionText() {
    var text = "";
    if (window.getSelection) {
        text = window.getSelection().toString();
    } else if (document.selection && document.selection.type != "Control") {
        text = document.selection.createRange().text;
    }
    return text;
}
function getStartOffset() {
    var sel = document.selection, range, rect;
    var x = 0, y = 0;
    if (sel) {
        if (sel.type != "Control") {
            range = sel.createRange();
            range.collapse(true);
        }
    } else if (window.getSelection) {
        sel = window.getSelection();
        if (sel.rangeCount) {
            range = sel.getRangeAt(0).cloneRange();
            if (range.getClientRects) {
                range.collapse(true);
            }
        }
    }
    return range.startOffset;
}
$("button").click(function(){
    var index = getStartOffset();
    var obj = getSelectionParentElement();
    var str = obj.innerHTML;
    var id = str.substr(0, index); // Gets the first part
    var text = str.substr(index);  // Gets the text part
    obj.innerHTML = "Ada"
    console.log("hasdhahdkashd",obj,getSelectionText())
    
});