How to set script include within field default value

[mkdj12]

Within this list collector, I am attempting to have this script include return a value for the field but I am unsure if the value that I am passing into the function (current.sys_id) is being sent over. 

Default Value:  javascript: new announcement_portal_util().getDefault(current.sys_id);

Script Include:

var announcement_portal_util = Class.create();
announcement_portal_util.prototype = {

    getDefault: function(announcement) {
        var gr = new GlideRecord("m2m_announcement_portal");
        gr.addQuery("sys_id", announcement);
        gr.query();
        if (gr.next()) {
            return gr.sp_portal;
        }
    },
    type: 'announcement_portal_util'
};

[Michael Fry1]

You can add a gs.log statement after the function to confirm you're getting the correct value.