Get the real width and height of an image with JavaScript? (in Safari/Chrome)

Question

I am creating a jQuery plugin.

How do I get the real image width and height with Javascript in Safari?

The following works with Firefox 3, IE7 and Opera 9:

var pic = $("img")

// need to remove these in of case img-element has set width and height
pic.removeAttr("width"); 
pic.removeAttr("height");

var pic_real_width = pic.width();
var pic_real_height = pic.height();

But in Webkit browsers like Safari and Google Chrome values are 0.

Answer 1

Webkit browsers set the height and width property after the image is loaded. Instead of using timeouts, I'd recommend using an image's onload event. Here's a quick example:

var img = $("img")[0]; // Get my img elem
var pic_real_width, pic_real_height;
$("<img/>") // Make in memory copy of image to avoid css issues
    .attr("src", $(img).attr("src"))
    .load(function() {
        pic_real_width = this.width;   // Note: $(this).width() will not
        pic_real_height = this.height; // work for in memory images.
    });

To avoid any of the effects CSS might have on the image's dimensions, the code above makes an in memory copy of the image. This is a very clever solution suggested by FDisk.

You can also use the naturalHeight and naturalWidth HTML5 attributes.