将XML数据加载到JavaScript中并使用XML数据更改div颜色

This is homework question requiring that I use color information collected in a XML file to change the color of twenty divs with a button. I have approached this by creating a single class of divs in the html document, loading the XML data into a Javascript file and iterating through the XML. I think the problem is that I am incorrectly loading the XML document into Javascript? I posted sections of the code as follows (I only posted one part of the css so it wouldn't be so long)This is homework question requiring that I use