jquery visible
snippet in javascript

element is hidden jquery

user7413

// Checks CSS content for display:[none|block], ignores visibility:[true|false]
$(element).is(":visible");

// The same works with hidden
$(element).is(":hidden");

jquery visible

user6410

$(":visible");
//or
$().is(":visible");

get count of class which is visible element

user1674

$(".level1:visible").length;