To add a class to an element, without removing/affecting existing values, append a space and the new classname, like so: document.getElementById("MyElement"). ... <看更多>

To add one or more CSS classes to the class list of an element, you use the add() method of the classList . For example, the following code adds the info class ... ... <看更多>

From: StackOverflow. To change all classes for an element: document.getElementById("MyElement").className = "MyClass";. To add an additional class to an ... ... <看更多>

addClass.js. /** * jQuery equivalent: [$.addClass](http://api.jquery.com/addclass/) * * Adds class to elements in the current selection. ... <看更多>