jquery check of element exists by class code example
Example 1: detect if an element has a class jQurey
$("#EL_ID").hasClass("CLASS_NAME");
Example 2: jquery check if element has class starting with
/* Answer to: "jquery check if element has class starting with" */
if(!$(this).is('[class*="answerbox"]')) {
//Finds element with no answerbox class
} else {
//The element has already an answerbox class
}