This gist showcases a way of how to get artist and title information from bop.fm to be used by browser extensions

bobfm_gettingSongInfos.js

var lastObservation = "";

var observer = new MutationObserver(function(mutations) {
    mutations.forEach(function(mutation) {
        var classes = mutation.target.className;
        var observation = "";
        if ( classes.indexOf("song-playing") > -1 )
        {
            var artist =   $(".song-info .artist")[0];
            artist = (artist && artist.textContent) ? artist.textContent.trim() : "";
            var title =    $(".song-info .title")[0];
            title = (title && title.textContent) ? title.textContent.trim() : "";
            var duration = $(".queue .current-song .duration")[0];
            duration = (duration && duration.textContent) ? duration.textContent.trim() : "";
            var progress = $(".current-song-wrapper .bar b")[0];
            progress = (progress && progress.style) ? progress.style.width : "";
            
            observation = "PLAYING: " + artist + " - " + title + " - " + duration + " - " + progress;
        }
        else if ( classes.indexOf("song-started") > -1 )
        {
            observation = "PAUSED";
        }
        else
        {
            observation = "STOPPED";
        }
        
        if (lastObservation != observation)
        {
            /* HANDLE NEW SONG */
            console.log(observation);
            lastObservation = observation;
        }
    });    
});

/* The easiest hook was so look for changes in the big and green play/pause button. */
/* The image of the button is controlled via a #page-playlist class name. */
var config = { attributes: true, attributeFilter: ["class"] };
var root = $("#page-playlist")[0];
observer.observe(root, config);

/* observer.disconnect(); */