Insert text into textarea with jQuery

From what you have in Jason's comments try:

$('a').click(function() //this will apply to all anchor tags
{ 
   $('#area').val('foobar'); //this puts the textarea for the id labeled 'area'
})

Edit- To append to text look at below

$('a').click(function() //this will apply to all anchor tags
{ 
   $('#area').val($('#area').val()+'foobar'); 
})

I use this function in my code:

$.fn.extend({
  insertAtCaret: function(myValue) {
    this.each(function() {
      if (document.selection) {
        this.focus();
        var sel = document.selection.createRange();
        sel.text = myValue;
        this.focus();
      } else if (this.selectionStart || this.selectionStart == '0') {
        var startPos = this.selectionStart;
        var endPos = this.selectionEnd;
        var scrollTop = this.scrollTop;
        this.value = this.value.substring(0, startPos) +
          myValue + this.value.substring(endPos,this.value.length);
        this.focus();
        this.selectionStart = startPos + myValue.length;
        this.selectionEnd = startPos + myValue.length;
        this.scrollTop = scrollTop;
      } else {
        this.value += myValue;
        this.focus();
      }
    });
    return this;
  }
});

input{width:100px}
label{display:block;margin:10px 0}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<label>Copy text from: <input id="in2copy" type="text" value="x"></label>
<label>Insert text in: <input id="in2ins" type="text" value="1,2,3" autofocus></label>
<button onclick="$('#in2ins').insertAtCaret($('#in2copy').val())">Insert</button>

It's not 100% mine, I googled it somewhere and then tuned for mine app.

Usage: $('#element').insertAtCaret('text');

have you tried:

$("#yourAnchor").click(function () {
    $("#yourTextarea").val("your text");
});

not sure about autohighlighting, though.

EDIT:

To append:

$("#yourAnchor").click(function () {
    $("#yourTextarea").append("your text to append");
});

What you ask for should be reasonably straightforward in jQuery-

$(function() {
    $('#myAnchorId').click(function() { 
        var areaValue = $('#area').val();
        $('#area').val(areaValue + 'Whatever you want to enter');
    });
});

The best way that I can think of highlighting inserted text is by wrapping it in a span with a CSS class with background-color set to the color of your choice. On the next insert, you could remove the class from any existing spans (or strip the spans out).

However, There are plenty of free WYSIWYG HTML/Rich Text editors available on the market, I'm sure one will fit your needs

• TinyMCE - JavaScript WYSIWYG editor
• Rich Text Editor - YUI Library
• 10 jQuery and Non-jQuery JavaScript Rich Text Editors

Another solution is described also here in case some of the other scripts does not work in your case.

$.fn.extend({
    insertAtCaret: function(myValue) {
        var elemSelected = window.getSelection();
        if(elemSelected) {
            var startPos = elemSelected.getRangeAt(0).startOffset;
            var endPos = elemSelected.getRangeAt(0).endOffset;
            this.val(this.val().substring(0, startPos)+myValue+this.val().substring(endPos,this.val().length));
        } else {
            this.val(this.val()+ myValue) ;
        }
    }
});