javascript function problem

Question

i need one more thing

i have

function show_image()
{
  document.write("<img src="+this.link+" ,alt="+this.alt+" ,width=600, height=400>");
}

function image(a,b,c)
{
  this.link=a;
  this.alt=b;
  this.thumb=c;
  this.zobraz=show_image;
}

image1=new image("img/img1.jpg","info image 1","thumb/img1");
image2=new image("img/img2.jpg","info image 2","thumb/img2");

and now, i am trying to do something like this:

function slideshow()
{
var i=1;
      while(i<3)
{
      document.write(image[i].zobraz());
i++
}
}

i don't know why, but this [i] thing is not working. Where is my mistake? thanks

Alexander Gessler · Accepted Answer · 2011-03-27 20:26:37Z

1

You should use an array to be able to subscript using []:

// create array to hold images
var images = [];

// load images and store them in the array
images.push(new image(...));
images.push(new image(...));

// .. now subscripting using [] works fine now
var i=0;
while(i<3)
{
   document.write(images[i].zobraz());
   i++
}

NOTE Array indices are zero-based, i.e. the first entry is at index 0!

answered Mar 27, 2011 at 20:26

Alexander Gessler

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4 Comments

ivanz Over a year ago

so, i can't continue this way? Basically, my constructor is useless now, right?

Alexander Gessler Over a year ago

It isn't useless, it is unrelated to the problem - the problem is simply that you didn't create an Array, so accessing using the [0] notation doesn't work.

xtofl Over a year ago

Small improvement: while( i < images.length ). In case a fourth and fifth image appear...

ivanz Over a year ago

this is great. Just one more thing : image.push(new image("img/img2.jpg","info o image 2","thumb/img2")); this is not working for me, but it is not such a big deal

Daniel A. White · Accepted Answer · 2011-03-27 20:27:55Z

0

You haven't actually created an array.

Try this:

var image = [];
image[0]=new image("img/img1.jpg","info image 1","thumb/img1");
image[1]=new image("img/img2.jpg","info image 2","thumb/img2");

and adjust your loop.

answered Mar 27, 2011 at 20:27

Daniel A. White

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Comments

Michael Berkowski · Accepted Answer · 2011-03-27 20:28:54Z

0

You are attempting to reference image1 and image2 as though they are array elements.

Instead of

image1=new image("img/img1.jpg","info image 1","thumb/img1");
image2=new image("img/img2.jpg","info image 2","thumb/img2");

Try this:

var image = [];
image[1] = new image("img/img1.jpg","info image 1","thumb/img1");
image[2] = new image("img/img2.jpg","info image 2","thumb/img2");

Now your function slideshow() should work as you've written it.

answered Mar 27, 2011 at 20:28

Michael Berkowski

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Comments

xtofl · Accepted Answer · 2011-03-27 20:52:27Z

0

In addition to the array-business stated in the other answers, you're still doing something awkward there:

document.write( image[i].zobraz() );

If you would expand the zobraz call you will see that it doesn't actually return anything. It would be best to either make zobraz return the "img" string, or to code simply image[i].zobraz();

answered Mar 27, 2011 at 20:52

xtofl

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2 Comments

ivanz Over a year ago

i got some weird error(it has displayed image, but alsostated undefined), but i couldn't find the problem. And this is the problem :) thanks

xtofl Over a year ago

@sevdah: I saved you asking the next question :)

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