trying to create a javascript object

Question

sorry - I know this is dead easy stuff, but I'm just trying to learn.

I'm trying to understand objects in Javascript, I'm just trying to get the obj.alertHello() to alert hello, but it's alerting 'undefined' why is this?? - I'm seriously going bald over this!

Thanks any help is most appreciated!! :)

var obj=function(){    
this.sayHello="hello";

};

obj.prototype={
    alertHello: function(sayHello){
    alert(sayHello)
    }
}

Quentin · Accepted Answer · 2012-05-07 19:18:33Z

1

sayHello and this.sayHello are different variables. You want something more like this:

var obj=function(){    
    this.sayHello="hello";
};

obj.prototype={
    alertHello: function(sayHello){
        alert(this.sayHello);
    }
};

var instance = new obj();
instance.alertHello();

answered May 7, 2012 at 19:18

Quentin

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1 Comment

user1380500 Over a year ago

Perfect, thank you Quentin! So, I can refer to any variable in the obj function at the top (is that what they call the constructor function??) by using the 'this' keyword, because it's a prototype right?? Thanks for every ones help on this!!

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