toolbar.js:100 Uncaught (in promise) TypeError: Cannot read property 'addEventListener' of null

at Toolbar._bindListeners (toolbar.js:100)

at new Toolbar (toolbar.js:55)

at Object._callee5$ (app.js:366)

at tryCatch (runtime.js:62)

at Generator.invoke [as _invoke] (runtime.js:288)

at Generator.prototype.(:50521/anonymous function) [as next] (http://localhost:50521/pdfview/web/viewer.js:2778:21)

at asyncGeneratorStep (app.js:1)

at _next (app.js:1)

at app.js:1

at new Promise (<anonymous>)

_bindListeners @ toolbar.js:100

Toolbar @ toolbar.js:55

_callee5$ @ app.js:366

tryCatch @ runtime.js:62

invoke @ runtime.js:288

prototype.(anonymous function) @ runtime.js:114

asyncGeneratorStep @ app.js:1

_next @ app.js:1

(anonymous) @ app.js:1

(anonymous) @ app.js:1

_initializeViewerComponents @ app.js:86

_callee$ @ app.js:144

tryCatch @ runtime.js:62

invoke @ runtime.js:288

prototype.(anonymous function) @ runtime.js:114

asyncGeneratorStep @ app.js:1

_next @ app.js:1

Promise.then (async)

run @ app.js:408

webViewerLoad @ viewer.js:216

原因：網站編碼問題