I have a class:

<style>
.jonny {
 color:"red"
}
</style>

in my element:

 <div class=jonny>abc</div> 

I want to check via JavaScript if class jonny have a content. sometime I want even to check where in my source it define. In which .css file it define.

I need to do it in runtime = in JavaScript.

Thank you j.r