This site only returns javascript. Here is an example, which can be embedded with the script below.
<script type="text/javascript" src="http://interactive.wbez.org/program-schedule/daily/2014-02-12.js"></script>
You must use the format daily/YYYY-MM-DD.js, days cannot be in the future, days cannot be before the example listed. If you see this page instead of javascript, then one of those rules was broken.
To decrease sizes, you can download a precompressed version by using a .jgz extension instead of .js. Here is an example like above.
The callback returns an array of arrays, looking like this loadProgramSchedule([["BBC World Service",0,300,"12am", ""Up-to-the-minute news..."]...]);
Remember, on your end of the request, you will need to program a javascript method named loadProgramSchedule. Regarding json output, it is designed for compactness; To see an implementation, see this example