不好意思，问题看得不够仔细，特意去翻了下MDN。当指定的属性不存在于元素上时，所有浏览器（Firefox、...
js letnonce=script.nonce; Specifications Specification DOM #ref-for-dom-element-getattribute① Report problems with this compatibility data on GitHub desktopmobile Chrome Edge Firefox Opera Safari Chrome Android Firefox for Android Opera Android
js letnonce=script.nonce; Specifications Specification DOM #ref-for-dom-element-getattribute① Report problems with this compatibility data on GitHub desktopmobile Chrome Edge Firefox Opera Safari Chrome Android Firefox for Android Opera Android
js letnonce=script.nonce; Specifications Specification DOM #ref-for-dom-element-getattribute① Report problems with this compatibility data on GitHub desktopmobile Chrome Edge Firefox Opera Safari Chrome Android Firefox for Android Opera Android