原型方法中的“ x未定义”

Question

I'm stuck with the following code:

I have the following code:

function Calendar() {
      this.month = "January";
    }
    Calendar.prototype.getMonth = function () {
        alert(cal.month);
    }
    $(document).ready(function() {
        var cal = new Calendar();
        var div_cal = document.getElementById("div_cal");
        var div_controls = document.getElementById("div_controls");
        div_controls.innerHTML='<input type="button" value="prev" onClick="cal.getMonth()">';
    });

when running this, the button is created but when pressing it the debug says: "'cal' is undefined"

Thanks for the help.

Answer 1

You have:

Calendar.prototype.getMonth = function () {
    alert(cal.month);
}

The cal variable is not defined here. Use this instead:

Calendar.prototype.getMonth = function () {
    alert(this.month);
}

Answer 2

Function Calender(){
this.month = "jan";
}
Calender.prototype.getMonth = function(){
alert(this.month);
}