<span class="teaser">text goes here</span>

<span class="complete"> this is the
complete text being shown</span>

<a class="more">more...</a>

<style>
  .complete {
    display: none;
  }
<style>

<script type="text/javascript">
  jQuery(document).ready(function ($) {
        $.fn.clicktoggle = function(a, b) {
            return this.each(function() {
                var clicked = false;
                $(this).click(function() {
                    if (clicked) {
                        clicked = false;
                        return b.apply(this, arguments);
                    }
                    clicked = true;
                    return a.apply(this, arguments);
                });
            });
        };

        $(".more").clicktoggle(function() {
          $(this).text("less..").siblings(".complete").show();
        }, function() {
          $(this).text("more..").siblings(".complete").hide();
        });
  });
</script>