Detect if an element is hidden or visible in jQuery-javascript?

I am not sure if you approach about ads is good or not, but to detect if an element is visible or not using jquery you can use the code below

$(element).is(":visible"); 

Or if there is any class of element which you want to test then you can apply this code

$(".Class").each(function() {
    if ($(this).css("visibility") == "hidden") {
        // code to handle non-visible state
    } else {
        // code to handle visible state
    }
});

You can use any of the above methods

About changing the state of element, yes after applying the above code, you can easily change the state, as per your needs using .show() or .hide()

You can also check if element is hidden or visible using below jQuery code

$('element:hidden')
$('element:visible')

Example, if we are trying to check HTML element with id "checkme"

if($('#checkme:hidden')){
   //element hiddent
}

if($('#checkme:visible')){
   //element visible
}

Thanks