source: extensions/reply_to/insertAtCaret.js @ 20968

/**
 * insertAtCaret function by sebagr.com
 * http://stackoverflow.com/questions/946534/insert-text-into-textarea-with-jquery/2819568#2819568
 */
jQuery.fn.extend({
  insertAtCaret: function(myValue){
    return this.each(function(i) {
      if (document.selection) {
        this.focus();
        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();
      }
    })
  }
});