<style>
.small  {height: 20px;}
.big    {height: auto;}
</style>


<div class="small">
    <p>Lorenter code hereem ipsum dolor sit amet, consectetur adipisicing elit, sed do
    eiusmod tempor incididunt ut labore et dolore magna aliqua.
    Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris
    nisi ut aliquip ex ea commodo consequat. Lorem ipsum dolor sit amet,
    consectetur adipisicing elit, sed do eiusmod tempor incididunt
    ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis
    nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo
    consequat.</p>
    <a href="#">Click to read more</a>
</div>

<script type='text/javascript'>
$(window).load(function(){
comment_reply = function (id){

   var e = $(id);
   e.toggle();
}
});
</script>

$('.wrapper').find('a[href="#"]').on('click', function (e) {
    e.preventDefault();
    $(this).closest('.wrapper').find('.small').toggleClass('small big');
});

$('.wrapper').find('a[href="#"]').on('click', function (e) {
    e.preventDefault();
    this.expand = !this.expand;
    $(this).text(this.expand?"Click to collapse":"Click to read more");
    $(this).closest('.wrapper').find('.small, .big').toggleClass('small big');
});

$(document).ready(function(){
    $(document).on('click', '.small a', function(){
        $('.small').addClass('big');
        $('.small').removeClass('small');
    });
    $(document).on('click', '.big a', function(){
        $('.big').addClass('small');
        $('.big').removeClass('big');
    });
});

.text.short {
    height: 50px;
    overflow: hidden;
}
.text.full {

}
.read-more {
    cursor: pointer;
    display: inline-block;
    font-weight: bold;
    padding: 3px;
    background-color: #06c;
    color: white;
    margin: 2px;
}

$(document).ready(function(){
    $(".read-more").click(function(){
        var $elem = $(this).parent().find(".text");
        if($elem.hasClass("short"))
        {
            $elem.removeClass("short").addClass("full");
        }
        else
        {
            $elem.removeClass("full").addClass("short");
        }
    });
});

[DEMO][2]

$('.wrapper').find('a[href="#"]').on('click', function (e) {
    e.preventDefault();
    this.expand = !this.expand;
    $(this).text(this.expand?"Click to collapse":"Click to read more");
    $(this).closest('.wrapper').find('.small, .big').toggleClass('small big');
});

[2]: http://jsfiddle.net/mWcmg/1/