[jQuery] is this a good way to test for the presence of a jquery plugin?

[Sam Sherlock]

I am using this to test for the presence of blockUI

        if((typeof $.blockUI) === 'object')    {
                  // set up blockUI
        }

also seems to work

        if((typeof $.fn.idTabs) === 'object')    {
            $('.idTabs').idTabs();
        }


does'nt work
        if((typeof $.fn.jScrollPane) === 'object')    {
            $('.scroll-pane').jScrollPane();
        }



it seems to not work with JSScrollBar though - so I thought perhaps there is
a better way

or should I go through the converluted apprpach of setting flags??

var isBlockUI = 1; // added to the plugin file to check elsewhere in other
scripts