How to insert text into a textarea where the cursor is

insertAtCaret.js

//
// jQuery version
// @author https://stackoverflow.com/a/15977052/2337281
// Example Usage:
// <textarea id="txt" rows="15" cols="70">There is some text here.</textarea>
// <input type="button" id="btn" value="OK" />
//

jQuery("#btn").on('click', function() {
        var $txt = jQuery("#txt");
        var caretPos = $txt[0].selectionStart;
        var textAreaTxt = $txt.val();
        var txtToAdd = "stuff";
        $txt.val(textAreaTxt.substring(0, caretPos) + txtToAdd + textAreaTxt.substring(caretPos) );
    });

//
// Plain JavaScript version
// @author https://stackoverflow.com/a/1064139/2337281
// Example Usage:
// <textarea id="textareaid"></textarea>
// <a href="#" onclick="insertAtCaret('textareaid', 'text to insert');return false;">Click Here to Insert</a>
//

function insertAtCaret(areaId,text) {
	var txtarea = document.getElementById(areaId);
	var scrollPos = txtarea.scrollTop;
	var strPos = 0;
	var br = ((txtarea.selectionStart || txtarea.selectionStart == '0') ? 
		"ff" : (document.selection ? "ie" : false ) );
	if (br == "ie") { 
		txtarea.focus();
		var range = document.selection.createRange();
		range.moveStart ('character', -txtarea.value.length);
		strPos = range.text.length;
	}
	else if (br == "ff") strPos = txtarea.selectionStart;
	
	var front = (txtarea.value).substring(0,strPos);  
	var back = (txtarea.value).substring(strPos,txtarea.value.length); 
	txtarea.value=front+text+back;
	strPos = strPos + text.length;
	if (br == "ie") { 
		txtarea.focus();
		var range = document.selection.createRange();
		range.moveStart ('character', -txtarea.value.length);
		range.moveStart ('character', strPos);
		range.moveEnd ('character', 0);
		range.select();
	}
	else if (br == "ff") {
		txtarea.selectionStart = strPos;
		txtarea.selectionEnd = strPos;
		txtarea.focus();
	}
	txtarea.scrollTop = scrollPos;
}