javascript - extend function in jquery -

i new query , trying understand below plugin function doing, not understanding.

var pluginname = 'widgets';  function plugin(element, options) {     /**      * variables.      **/     this.obj = $(element);     this.o = $.extend({}, $.fn[pluginname].defaults, options);     this.objid = this.obj.attr('id');     this.pwctrls = '.jarviswidget-ctrls'     this.widget = this.obj.find(this.o.widgets);     this.toggleclass = this.o.toggleclass.split('|'); } 

i thankful if 1 great in jquery explain step step.

thank in advance.

regards, mona

jquery's $.extend merges contents of 2 or more objects first object.

in other words, takes object default settings plugin, gets object passed in options, , joins them options overwrite defaults.

example

var defaults = {     setting1 : '2',     setting2 : true }  function plugin(options) {     var settings = $.extend({}, defaults, options);      /* settings contain      {         setting1: '2',         setting2: false     }     */ }  plugin({     setting2: false // options, change default settings }); 

the plugin function seems part of sort of widget build plugins, sets few general settings instance.