2 回答Uncaught TypeError: Cannot read property 'className' of null

1 回答為什么報錯，出現Cannot read property 'length' of null at switchSlider (index.html:212) at window.onload (index.html:224)

1 回答Uncaught TypeError: Cannot read property 'replace' of undefined

2 回答Uncaught TypeError: Cannot read property 'className' of undefined(主圖顯示不出來)