examples/bower_components/polymer/polymer.js
function(anew, old, className) {
      if (old) {
        old.classList.remove(className);
      }
      if (anew) {
        anew.classList.add(className);
      }
    }
function(anew, old, className) {
      if (old) {
        old.classList.remove(className);
      }
      if (anew) {
        anew.classList.add(className);
      }
    }
function ( anew , old , className ) { if ( old ) { old . classList . remove ( className ) ; } if ( anew ) { anew . classList . add ( className ) ; } }
Remove class from old, add class to anew, if they exist.

@param classFollows
@param anew A node.
@param old A node
@param className
Remove class from old add class to anew if they exist .