// here parameter element is a jquery wrapped object and not html element



function isVisible(element){
if(elem.is(":visible")){
return true;
}
else{
return false;
}
}


You would use it like below

if(isVisible($('#elementId')){
alert("Visible");
}



Read more: http://feeds.dzone.com/~r/dzone/snippets/~3/0fx-_FxmKAE/13701