Using jQuery 1.11.3 in Chrome, I'm not sure if this is a bug or a "nice to have feature", but if you try to do a $.param() on something undefined it throws the error:

Cannot read property 'jquery' of undefined

This mainly happens when let's say your passing parameters into a function and sometimes you don't want/need to pass any:

function Example (parametersToPass) {
    $.param( parametersToPass );
}
Example(); // <-- will error out.

The easiest fix is to simply:

$.param( parametersToPass || '' );