博客园markdown编辑器代码折叠

<script type="text/javascript">
        $(document).ready(function () {
            var pres = $("pre");
            for (var i = 0; i < pres.length; i++) {
                $(pres[i]).attr('id', 'pre' + i);
                $(pres[i]).children('code').hide();
                $(pres[i]).prepend('<button id="btn'+ i +'" onclick="view_code(\'pre'+ i +'\');">view code</button>');
            }
        });
        function view_code (id) {
            var btn_text =  document.getElementById(id).children[0].innerText;
            var style;
            var status;
            if(btn_text == 'view code') {
                style = '""';
                status = 'hide code';
            } else {
                style = 'display: none;';
                status = 'view code';
            }
            document.getElementById(id).children[0].innerText = status;
            document.getElementById(id).children[1].style = style;
        }
</script>