how to add and remove css class

Question

how to remove CSS default class

This is my div

This is my css class

#messageContai         


        

Answer 1

You aren't dealing with a class. You have default rules applied to the ID element. As such, you should really only need to add the new class:

$("#messageContainer").addClass("newRules");

Any rules that aren't overwritten can be overwritten with the css() method:

$("#messageContainer").css({
  'font-weight':'bold',
  'color':'#990000'
}).addClass("newRules");