Test Channel by Class

channel.js

var channel;

if ($(body).hasClass('fbfanpage')) {
    channel = 'fbfanpage';
} else if ($(body).hasClass('fbcanvas')) {
    channel = 'fbcanvas';
} else if ($(body).hasClass('microsite')) {
    channel = 'microsite';
} else if ($(body).hasClass('mobile')) {
    channel = 'mobile';
} else {
    channel = 'Unknown';
}

// Now you can use the variable "channel" for conditional JavaScript features