in odoo @ \https://www.odoo.com/documentation/9.0/howtos/web.html

openerp.oepetstore = function(instance, local) {
    var _t = instance.web._t,
        _lt = instance.web._lt;
    var QWeb = instance.web.qweb;

    local.HomePage = instance.Widget.extend({
        start: function() {
            console.log("pet store home page loaded");
        },
    });

    instance.web.client_actions.add(
        'petstore.homepage', 'instance.oepetstore.HomePage');
}

most of the code in the odoo document is in v8 js, but i am trying to learn odoo 9 js. how to call instance.web.client_actions in odoo 9 and what is local mean for

i have done this !!!

odoo.define('oepetstore.petstore', function(require) {	
    "use strict";

    var core = require('web.core');
    var _t = core._t;
    var _lt = core._lt;
    var QWeb = core.qweb;     
      
});