Answers for "if something has a class jquery"

jquery hasclass

if ($( "#foo" ).hasClass('className')) {
	$( "#foo" ).removeClass( 'className');
} else {
  $( "#foo" ).addClass( 'className');
}

if a class exists jquery

if ($(".mydivclass").length){
    // Do something if class exists
} else {
    // Do something if class does not exist
}