CSS 2.1 errors: not a known property name

Question

Here is my code, I got it from an AJAX sample:

body, div, p, h1, h2, h3, h4, ul, li, table
{
    margin:0;
    padding:0;
    border:none;
}

body
{
    backgrou         


        

Answer 1

The errors you are getting are validation errors. Opacity and filter are not in the CSS 2.1 spec despite being supported by all major browsers.