One of the undocumented features of the Appcelerator WebSDK is the built-in support of transparent PNG images for IE6. A simple Google search will show you many, many different Javascript code snippets that you can put in your app to apply the PNG transparency filter on your images. But we thought we could provide this in our framework for you so you don’t have to worry about it.

The only problem has been that you couldn’t control exactly which images you want the filter to apply to. For example, if the filter applied to a div that had a background-image and a position, then potentially nothing inside that div would be clickable. And you also probably don’t want the extra processing on PNG images that don’t have any transparency to begin with.

So on the next released version of the WebSDK (2.1.3), we’ll have a .htc file that you can use in your CSS to control which images you want the PNG fix to apply to. For example you can do

.png 
{
   behavior: url(/images/iepngfix.htc);
}

to apply on all elements that have the class “png” or you can do

img, div 
{
   behavior: url(/images/iepngfix.htc);
}

to simply apply on all img and div elements.

Having these .htc files may not be the best thing in the world, but at least you can have control on where the PNG fix is applied.

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