Jquery 显示隐藏更多文本的代码举例

<script type="text/javascript">
/**
 * jquery 显示或隐藏文本
 * www.jb200.com
 * Edit: 2013/5/8 星期三
*/
 $(function(){
    $(".content").each(function(){
        var $targetEle = $(this).find("span").first();
        var $btnCtrl = $(this).find("span").last();
        var strAll = $targetEle.text();   
        if (strAll.length >30)
        {
            var sonStr = strAll.substr(0,30);
            $targetEle.text(sonStr)
            $btnCtrl.click(function(){
                if ($btnCtrl.text().substr(0,5)=="More↓")
                {
                    $targetEle.text(strAll);
                    $btnCtrl.text("More↑");
                }
                else{
                    $targetEle.text(sonStr)
                    $btnCtrl.text("More↓");
                }         
            });
        }
        else{$btnCtrl.text("")}   
    });
 });
</script>