Parmval from a UI Action is not showing up Client Script (both in same tabe)

[rob_kling]

I am experiencing some behaviour whereby I am using a UI Action to produce a separate form and  invoking an onLoad client script. When selecting the UI Action for the first time the parm value is not being picked up the client script, subsequent actions result in the value being passed to the client script

UI Action     

var uri = action.getGlideURI();

var path = uri.getFileFromPath() + '';

path = path.substring(0, path.length - 5) + '.do';

uri.set('sys_id', '-1');

uri.set('u_ci_task_type', 'quote prep'); //Passing in Quote Prep for Ci Case Task Client Script to read

path = checkWizard(uri, path);

if (path)

    action.setRedirectURL(uri.toString(path));

action.setNoPop(true);

function checkWizard(uri, path) {

    var already = uri.get('WIZARD:action');

    if (already == 'follow')

        return null;

    var wizID = new GlideappWizardIntercept(path).get();

    if (!wizID)

        return path;

    uri.set('sysparm_parent', wizID);

    uri.deleteParmameter('sysparm_referring_url');

    uri.deleteMatchingParameter('sysparm_list_');

    uri.deleteMatchingParameter('sysparm_record_');

    uri.deleteParmameter('sys_is_list');

    uri.deleteParmameter('sys_is_related_list');

    uri.deleteParmameter('sys_submitted');

    uri.deleteParmameter('sysparm_checked_items');

    uri.deleteParmameter('sysparm_ref_list_query');

    uri.deleteParmameter('sysparm_current_row');

    uri.set('sysparm_referring_url', uri.toString());

    uri.deleteMatchingParameter('fancy.');

    uri.deleteMatchingParameter('sys_rownum');

    uri.deleteMatchingParameter('sysparm_encoded');

    uri.deleteMatchingParameter('sysparm_query_encoded');

    uri.deleteParmameter('sysparm_refer');

    current.work_notes = 'Rate change accepted';

    return 'wizard_view.do';

}

Client Script

function onLoad() {

    //Populate the variables with the parameters passed in the URL

    //Use the 'getParmVal' function below to get the parameter values from the URL

    var url = top.location.href;

    var Catvalue = new URLSearchParams(url).get("u_ci_task_type");

    alert("BCO0:" + Catvalue);

    var gUrl = new GlideURL();

    gUrl.setFromCurrent();

    var Catvalue2 = gUrl.getParam("u_ci_task_type");

    alert("BCO02:" + Catvalue2);

    var cat = getParmVal('u_ci_task_type');

    g_form.setValue('u_ci_task_type', cat);

    alert("BCO" + cat);

Results

1st occcurrence

BCO0 ; null

BCO02 : undefined

BCO undefined 

2nd occurence

BCO0 : null

BCO02 quote+prep

BCO quote_prep