文章源自:http://viralpatel.net/blogs/dynamically-shortened-text-show-more-link-jquery/

Dynamically shortened Text with “Show More” link using jQuery

Update: The plugin is now on GitHub: https://github.com/viralpatel/jquery.shorten

Facebook user updates has a great functionality. If the comment text is larger than few characters, the extra words are hide and a show more link is presented to user. This way you can keep long text out of the view to user and stop the cluttering of page. Also interested users can click on more link and see the full content.

Here is a simple tutorial to achieve this using jQuery / Javascript.

The HTML

Below is the sample text. Each text is wrapped in a DIV tag. Note that we have added a class “more” in each div. This class will decide if a text needs to be shortened and show more link showed or not.

<div class="comment more">
    Lorem ipsum dolor sit amet, consectetur adipiscing elit.
    Vestibulum laoreet, nunc eget laoreet sagittis,
    quam ligula sodales orci, congue imperdiet eros tortor ac lectus.
    Duis eget nisl orci. Aliquam mattis purus non mauris
    blandit id luctus felis convallis.
    Integer varius egestas vestibulum.
    Nullam a dolor arcu, ac tempor elit. Donec.
</div>
<div class="comment more">
    Duis nisl nibh, egestas at fermentum at, viverra et purus.
    Maecenas lobortis odio id sapien facilisis elementum.
    Curabitur et magna justo, et gravida augue.
    Sed tristique pellentesque arcu quis tempor.
</div>
<div class="comment more">
    consectetur adipiscing elit. Proin blandit nunc sed sem dictum id feugiat quam blandit.
    Donec nec sem sed arcu interdum commodo ac ac diam. Donec consequat semper rutrum.
    Vestibulum et mauris elit. Vestibulum mauris lacus, ultricies.
</div>

The CSS

Below is the CSS code for our example. Note the class “.morecontent span” is hidden. The extra text from the content is wrapped in this span and is hidden at time of page loading.

a {
    color: #0254EB
}
a:visited {
    color: #0254EB
}
a.morelink {
    text-decoration:none;
    outline: none;
}
.morecontent span {
    display: none;
}
.comment {
    width: 400px;
    background-color: #f0f0f0;
    margin: 10px;
}

The Javascript

Below is the Javascript code which iterate through each DIV tags with class “more” and split the text in two. First half is showed to user and second is made hidden with a link “more..”.

You can change the behaviour by changing following js variables.

• showChar: Total characters to show to user. If the content is more then showChar, it will be split into two halves and first one will be showed to user.
• ellipsestext: The text displayed before “more” link. Default is “…”
• moretext: The text shown in more link. Default is “more”. You can change to “>>”
• lesstext: The text shown in less link. Default is “less”. You can change to “<<"

$(document).ready(function() {
    var showChar = 100;
    var ellipsestext = "...";
    var moretext = "more";
    var lesstext = "less";
    $('.more').each(function() {
        var content = $(this).html();
 
        if(content.length > showChar) {
 
            var c = content.substr(0, showChar);
            var h = content.substr(showChar-1, content.length - showChar);
 
            var html = c + '<span class="moreellipses">' + ellipsestext+ '&nbsp;</span><span class="morecontent"><span>' + h + '</span>&nbsp;&nbsp;<a href="" class="morelink">' + moretext + '</a></span>';
 
            $(this).html(html);
        }
 
    });
 
    $(".morelink").click(function(){
        if($(this).hasClass("less")) {
            $(this).removeClass("less");
            $(this).html(moretext);
        } else {
            $(this).addClass("less");
            $(this).html(lesstext);
        }
        $(this).parent().prev().toggle();
        $(this).prev().toggle();
        return false;
    });
});

Update

The above code is modified into jQuery plugin. Also it has now been enhanced. HTML tags are now parsed properly within text to preserve its uniformity while shorting the text. Please check latest plugin code on GitHub. https://github.com/viralpatel/jquery.shorten

jQuery Plugin

Code

/*
 * jQuery Shorten plugin 1.0.0
 *
 * Copyright (c) 2013 Viral Patel
 * http://viralpatel.net
 *
 * Dual licensed under the MIT license:
 *   http://www.opensource.org/licenses/mit-license.php
 */
 
 (function($) {
    $.fn.shorten = function (settings) {
     
        var config = {
            showChars: 100,
            ellipsesText: "...",
            moreText: "more",
            lessText: "less"
        };
 
        if (settings) {
            $.extend(config, settings);
        }
         
        $(document).off("click", '.morelink');
         
        $(document).on({click: function () {
 
                var $this = $(this);
                if ($this.hasClass('less')) {
                    $this.removeClass('less');
                    $this.html(config.moreText);
                } else {
                    $this.addClass('less');
                    $this.html(config.lessText);
                }
                $this.parent().prev().toggle();
                $this.prev().toggle();
                return false;
            }
        }, '.morelink');
 
        return this.each(function () {
            var $this = $(this);
            if($this.hasClass("shortened")) return;
             
            $this.addClass("shortened");
            var content = $this.html();
            if (content.length > config.showChars) {
                var c = content.substr(0, config.showChars);
                var h = content.substr(config.showChars, content.length - config.showChars);
                var html = c + '<span class="moreellipses">' + config.ellipsesText + ' </span><span class="morecontent"><span>' + h + '</span> <a href="#" class="morelink">' + config.moreText + '</a></span>';
                $this.html(html);
                $(".morecontent span").hide();
            }
        });
         
    };
 
 })(jQuery);

Usage

Step 1: Include the jQuery plugin in your HTML

<script type="text/javascript"
    src="http://viralpatel.net/blogs/demo/jquery/jquery.shorten.1.0.js"></script>

 Step 2: Add the code to shorten any DIV content. In below example we are shortening DIV with class “comment”.

<div class="comment">
    This is a long comment text.
    This is a long comment text.
    This is a long comment text.
    This is a long comment text. This is a long comment text.
</div>
<script type="text/javascript">
    $(document).ready(function() {
     
        $(".comment").shorten();
     
    });
</script>

 You may want to pass the parameters to shorten() method and override the default ones.

$(".comment").shorten({
    "showChars" : 200
});
 
 
$(".comment").shorten({
    "showChars" : 150,
    "moreText"  : "See More",
});
 
$(".comment").shorten({
    "showChars" : 50,
    "moreText"  : "See More",
    "lessText"  : "Less",
});