How do I view the properties of a DOM object in Chrome Developer?

What you want to do is add attributes tag to the end. This will return an array of the attributes. You may need the JavaScript Kit to actually do this, but then you can just have a loop to go through the attributes no matter how many there are.

sourceAttributes = document.getElementsByTagName('source')[0].attributes
for(int i=0; i<sourceAttributes.length; i++) {
    console.debug(sourceAttributes[i]);
}

In Chrome you should use the dir method:

console.dir(document.getElementsByTagName('source')[0]);​

Or for the current inspected/highlighted element:

console.dir($0);​

This will give you a result like so: