if($("#").is(":visible")) code example
Example 1: CHECK IF element is hidden jquery
// Checks CSS content for display:[none|block], ignores visibility:[true|false]
$(element).is(":visible");
// The same works with hidden
$(element).is(":hidden");
Example 2: jquery is element hidden
// Checks css for display:[none|block], ignores visibility:[true|false]
$(element).is(":hidden");