autolink all ipynb link to nbviewer

autoipynb.js

url_root='http://nbviewer.ipython.org/';
url=null;

var transform_url = function(href){
    if( href===undefined){return}
    if (href.search(/^https?:\/\/nbviewer/) == 0 ){
        console.log('case 1')
        return null
    } else if (href.search(/^https?:\/\/gist\.github\.com\/(?:\w+\/)?[a-f0-9]+$/) !== -1) {
        console.log('case 2')
        gist = href.match(/^https?:\/\/gist\.github\.com\/(?:\w+\/)?([a-f0-9]+)$/);
        return  url_root + gist[1];
    } else if (href.search(/^https:\/\/.*\.ipynb$/) !== -1) {
        console.log('case 3')
        path = href.match(/^https:\/\/(.*\.ipynb)$/);
        return url_root + 'urls/' + path[1];
    } else if (href.search(/^http:\/\/.*\.ipynb$/) !== -1) {
        console.log('case 4')
        path = href.match(/^http:\/\/(.*\.ipynb)$/);
        return url_root + 'url/' + path[1];
    }

    console.log('case none')
    return null
}

autoviewlink = function(index,link){
    var href = link.href
    var nhref = transform_url(href)
    console.log('nhref', nhref);
    if(nhref != null){
        $(link).after($('<a/>').attr('href',nhref).text(' (nbviewer)'))
    }
}

$.each($('a'),autoviewlink)