So the alert gives undefined values for the width and height. I think the w and h values of the image from the img.onload calculation is not being passed to the values to return, or it may be returning w and h **before** the onload calculates them:

```
function getMeta(url){
 var w; var h;
 var img=new Image;
 img.src=url;
 img.onload=function(){w=this.width; h=this.height;};
 return {w:w,h:h}    
}

// "http://snook.ca/files/mootools_83_snookca.png" //1024x678
// "http://shijitht.files.wordpress.com/2010/08/github.png" //128x128

var end = getMeta("http://shijitht.files.wordpress.com/2010/08/github.png");
var w = end.w;
var h = end.h;
alert(w+'width'+h+'height');

```

How can I have the alert show the correct width and height? 

<http://jsfiddle.net/YtqXk/>