How do I load a CZML file into the Cesium browser from the hard drive?
The browser can’t read directly from your local machine, but you can host your files on a local server, just like Cesium needs a server to run. For instance, if my Cesium application were at localhost:8080/app.js , I could read from a czml file hosted at localhost:8080/data.czml. The path is specified relative to the page location.
Here’s a code example: http://cesiumjs.org/Cesium/Apps/Sandcastle/index.html?src=CZML.html&label=All
This recent thread may be of interest: https://groups.google.com/d/msg/cesium-dev/Fk7tcaitXds/XVMQrQaXAwAJ
hope that helps,