JavaScript Prototype: An Interesting Object has no method Error

Question

I'm making an HTML5 game and thinking 15 levels for it. I have an levels class that include level objects. This is the code part of it.

  function levels(){

        this.allLevels=[];

            for (var i = 1; i <=15; i++) {
                this.allLevels[this.allLevels.length]=new level(); //LEVEL OBJECTS CREATED INTO OBJECT
                this.allLevels[this.allLevels.length-1].levelNumber=i; //LEVEL NUMBERS ARE SET
                (i==1)? this.allLevels[this.allLevels.length-1].state='ZERO':this.allLevels[this.allLevels.length-1].state='LOCKED'; //LEVEL STATES ARE SET     
            }

    }

As you might see, I have an allLevels array to keep the level information. So far so good everything works. After creating this class I added init and draw methods to this class. Here it is;

levels.prototype.initAll = function(){
        for(var i=0;i<=15;i++){
            this.allLevels[i].initAllCoor();
        }
    };

    levels.prototype.draw=function(){
        this.cleanCanvas();

        for(var i=0;i<=15;i++){
            this.allLevels[i].drawLevelIcon();
        }

    };

    levels.prototype.cleanCanvas=function(){
        ctxCanvasLevels.clearRect(0,0,800,570);
    };

It has just three methods for now. The functions you see(initAllCoor and drawLevelIcon) are the level object's methods. When I called these methods, everything works.

You can say if everything works what are you asking. Although everything works smoothly, I'm getting error at the Chrome's console.

 Uncaught TypeError: Cannot call method 'initAllCoor' of undefined 
 Uncaught TypeError: Cannot call method 'drawLevelIcon' of undefined 

I can't understand, it says 'cannot call' but it does. Because of this errors I can't use console.log function, too.

Answer 1

When you create the levels:

    for (var i = 1; i <=15; i++) {

In the "initAll" function:

    for(var i=0;i<=15;i++){

There is never a level 0, yet the "initAll" function expects one.

It's not invalid or wrong , but it's somewhat weird to start filling a JavaScript array at position 1 instead of 0.