check when element gets class jquery code example

Example: button has class or not c#

//How to check if class attribute contains something?
//https://stackoverflow.com/questions/34992613/how-to-check-if-class-attribute-contains-something
//el is the web element
if(el.getAttribute("class").split(" ").contains("disabled"))
{  
    //your code
}

or 

#region HTML Method
public static bool hasClass(WebControl element, string strClass)
{
  return Convert.ToString(element.Attributes["class"]).Split(' ').Contains(strClass);
}
#endregion