Q:

How can i delete javascript Object (John Resig - Simple Inheritance)?

My code:
myobj = new Object();
classes.testegy = Class.extend({
    init: function (token) {
        console.log("test egy");
        setInterval(function () {
            console.log('hello');
        }, 300);
    },
    testt: function () {
        console.log("luli");
    }
});
classes.testketto = Class.extend({
    init: function (token) {
        console.log("test ketto");
    }
});
classes.site = Class.extend({
    init: function (token) {
        var myobj = new Object();
        myobj.lel1 = new classes.testegy();
        myobj.lel2 = new classes.testketto();
        console.log(myobj);
        delete myobj.lel1;
        myobj.lel1.testt();
    }
});
var class = new classes.site();

If I delete the myobj.lel1 object, it will be deleted, but the setInterval goes in the testegy class. Why? How can I full delete Object? Thanks
edited: 
some example, when not use setInterval, use click, and console log.
classes.testegy = Class.extend({
init: function(token){
    console.log("test egy");
    $(".piii").live("click", function() {
        console.log("hello");
    });

},
foo: function() {
    console.log("pina");
}
});

classes.testketto = Class.extend({
init: function(token){
    console.log("test ketto");
}   
});

classes.site = Class.extend({
init: function(token){
    var myobj = new Object();

    myobj.lel1 = new classes.testegy();
    myobj.lel2 = new classes.testketto();

    console.log(myobj);

    delete myobj.lel1;
    myobj.lel1 = new classes.testegy();
    delete myobj.lel1;
    myobj.lel1 = new classes.testegy();
    delete myobj.lel1;
    myobj.lel1 = new classes.testegy();

}   
});

return: 1 click event -> 4x click = 4x console log :( it was created 4 shadow object.

A:

You need to define cleaning function. First, hold the reference to setInterval:
init: function(token){
    console.log("test egy");
    this.interval = setInterval(function() { console.log('hello'); }, 300);
}

then define cleaning function (in prototype):
clean: function() {
    clearInterval(this.interval);
}

and finally call myobj.lel1.clean() before deleting.
EDIT
The problem with the edited code is different. Look at this:
init: function(token){
    console.log("test egy");
    $(".piii").live("click", function() {
        console.log("hello");
    });
}

Whenever you initialize new object, this function adds new handler to click event on .piii. What you have to do is to use this code:
$(".piii").live("click", function() {
    console.log("hello");
});

outside an object definition. Or you can use $(".piii").unbind('click').click(/* handler */) inside init.
BTW. .live method is outdated. Use .on now.

