Determine if CSS property is set to a certain value?

Use

if( $("#test").css('display') == 'block') {

I’m fairly sure .css(), returning a calculated value, will always return a lower case result – the docs say nothing on this. To make totally sure, you could do a

if( $("#test").css('display').toLowerCase() == 'block') {

while you can rely on display giving reliable results, note that some CSS properties will not always show up the way they were defined. For example

a { color: red }

will turn out rgb(255,0,0); when queried using .css().