has_class.js

// hasClass, takes two params: element and classname
function hasClass(el, cls) {
  return el.className && new RegExp("(\\s|^)" + cls + "(\\s|$)").test(el.className);
}


/* use like below */
// Check if an element has class "foo"
if (hasClass(element, "foo")) {

  // Show an alert message if it does
  alert("Element has the class!");
}