Do you sometimes find errors in your CSS or desire to make some CSS improvements? If so, how many times to you find yourself applying and checking changes before you’re satisfied? Do you sometimes wonder if your site looks good on an 800×600 monitor? Do you sometimes wonder what could be causing your javascript to fail? If you’re tired of all of the above (especially repetitively applying and checking CSS changes), then take a look at the Web Developer Extension in this week’s PUM, Web Developer First-Aid.