javascript using object between js files.

[genesistr]

Hi,
I have Image.js and Main.js files. I create image object like test = new Image(...);
and it can be seen on screen but when i try to do call Move method like
test.Move(x,y); it crashes. Is there anyway to do that?

My code :

main.js:

var objBall = new Image("abc.gif", 0, 0, visible);
objBall.Move(50,50);

image.js

function ImageDeneme(path, x, y, visible)
{
    this.image = document.createElement("img");
    this.image.src = path;
    document.body.appendChild(this.image);
    this.Move = Move;
    
    return this.image;
}

function Move(x, y)
{
    this.image.style.left = x + "px";
    this.image.style.top = y + "px";
}

waiting for your answers :)

[Dormilich]

I'd expected it to crash on new Image() (ther is a built in image object which you call with the wrong parameters.

further, the Move() function is not part of the Image object.

currently I'm not sure, whether this will work since the shown code either doesn't make sense or doesn't seem likely to work together.

and while we're at OOP, in Javascript methods are better defined through prototyping:

ImageDeneme.prototype.Move = function(x, y) {
  // code comes here
}

[genesistr]

acctually i handle that problem and it works now but i have problem with inheritance now.

ImageClass.prot otype = new Drawable(...);
ImageClass.cons tructor = ImageClass;

but i got "prototype is read-only" error. I'm working on a different platform but it supports javascript and as i got, it has different version of js.

could you tell how to inherit from a super class?

[gits]

here is a very basic example:

// superclass constructor
function OBJ() {
}

// a method
OBJ.prototype.fooMethod = function() {
    alert('OBJs fooMethod');
}

// childclass constructor
function myOBJ() {
}

// inherit from OBJ
myOBJ.prototype = new OBJ;

// fix the constructor
myOBJ.prototype.constructor = myOBJ;

// create a instance of myOBJ
var o = new myOBJ;

// call the inherited method
o.fooMethod();

kind regards

[genesistr]

im doing the same but as i said i got "prototype is read-only" error.

[gits]

what's your environment ... the shown way is the 'classical' way to do it.

[genesistr]

@gits your method is working but i couldnt find how to call base constructor.

function Drawable(dElement)
{
    this.element = dElement;
    ....
}

Image.prototype = new Drawable;
Image.prototype.constructor = Image

function Image(path, x, y, visible)
{    
    debugtext("ImageDeneme");
    this.image= document.createElement("img");
    this.image.src = path;
    this.image.style.position = "absolute";

    //Drawable.call(this,this.image);  //I thought it should work but it didnt.
 
    document.body.appendChild(this.element);
};

i wonder how to call base class' constructor.

[gits]

here the short example for the base-constructor call:

// superclass constructor
function OBJ(p) {
   this.bar = p;
}

// a method
OBJ.prototype.fooMethod = function() {
   alert('OBJs fooMethod');
}

// childclass constructor
function myOBJ() {
   OBJ.prototype.constructor.apply(this, arguments);
}

// inherit from OBJ
myOBJ.prototype = new OBJ;

// fix the constructor
myOBJ.prototype.constructor = myOBJ;

// create a instance of myOBJ
var o = new myOBJ('foo');

alert(o.bar);

[genesistr]

thanks gits.
all works fine now :)

[gits]

no problem ... just post back to the forum in case you have more questions :)

kind regards