相关疑难解决方法(0)

在我的Rails应用程序中,我的折叠navebar在滚动时不会改变它的样式,并且在inspect元素控制台中也会发生错误:

TypeError: elem is null
      elem.classList.add( c );

发生错误的Classie .js:

( function( window ) {

'use strict';

// class helper functions from bonzo https://github.com/ded/bonzo

function classReg( className ) {
  return new RegExp("(^|\\s+)" + className + "(\\s+|$)");
}

// classList support for class management
// altho to be fair, the api sucks because it won't accept multiple classes at once
var hasClass, addClass, removeClass;

if ( 'classList' in document.documentElement ) {
  hasClass = function( elem, c ) {
    return elem.classList.contains( c …