What is wrong in this javascript code.

Question

What i am trying to achieve is creating some objects by following a better pattern. I am using Raphael.js library for creation of graphical shapes.

Problem is at the line:

X: "" + this.canvas_X + this.paper["width"]/2 - self.width/4,

The error i am getting is :

Uncaught TypeError: Cannot read property 'width' of undefined

I figured out that error is at this.paper["width"]/2. I am new to using javascript and not able to understand what error i am doing

var Graphics={
        create_canvas: function(){
                $("#canvasdiv").append("<div id='id1' width='80px' height='50px'></div>");
        },
        canvas_X:get_LEFT_TOP("canvasdiv")[0],
        canvas_Y:get_LEFT_TOP("canvasdiv")[1],
        canvas_width:function(){return $("#canvasdiv").width()},
        canvas_height:function(){return $("#canvasdiv").height()},
        paper:{
            width:900,
            height:700,
            create: function(){
                return new Raphael(document.getElementById('canvasdiv'),this.width,this.height);
            }
        },
        vswitch:{
            color:"Black",
            text:"vSwitch",
            width:"150",
            height:"150",
            X: "" + this.canvas_X + this.paper["width"]/2 - self.width/4,
            Y: Graphics.canvas_Y,
            delay:"2000",
            create: function(paper){
                setTimeout(function(){
                        paper.rect(X,Y,width,height).attr({fill : "black"})
                        },delay);
            }
        },
}

This is the way the call is being made:

 Graphics.create_canvas();
    p=Graphics.paper.create();
    Graphics.vswitch.create(p);

Answer 1

Hi, I think you have to catch the undefined width property with the function console.log() and see the result
in your browser console. Like this :

console.log('firstwidth ' + this.paper["width"]);
console.log('secondwidth ' + self.width ) ;