Embedly's iframe in a fluid layout using inline replace.

embedly.fluid.js

(function() {
 
    window.embedlyFluid = function(selector, key, options) {
        $(selector).each(function() {
     
            // set the video to the width of the parent container
            var width = $(this).parent().width();
     
            defaults = {
                secure: true
                , frame: true
                , maxwidth: width
            }

            query = $.extend({}, defaults, options);
            $(this).embedly({
                key: key
                , query: query
            });
        });
    };
 
})();

// here is how to use embedlyFluid.
embedlyFluid('.document a', EMBEDLY_KEY);

// adding auto-play
embedlyFluid('.document a', EMBEDLY_KEY, {autoplay: true});

// autoplay and disable embedly iframes
embedlyFluid('.document a', EMBEDLY_KEY, {autoplay: true, frame: false});

// finally forcing your own maxwidth.
embedlyFluid('.document a', EMBEDLY_KEY, {maxwidth: 200});

An example of the script in action here:

http://jerviswhitley.com/embedly-fluid-iframe-video/