This is a common js dilemma in js when accessing methods from other methods. Where "this" points depends on where and how it is called.
Try: function MainPage(){ var that = this; // Add this line this.init = function(){ $('#sample').click(function(){ // here is my problem, inside this anonymous function how can I access the method_one function? that.method_one(param_1, param_2); // Modify this line }); } this.method_one = function(param_1, param_2){ $(param_1).load(param_2); } }