Insert at caret

insert.js

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