I added the tag code in the local node_module/vue/dist/vue.runtime.common.js and vue.runtime.esm.js. Running npm run build, found that the terminal would run the tag code in vue.runtime.common.js. I don"t know why. My understanding is that npm run build executes the webpack configuration, finds the portal file, and executes the code in the portal file. But the problem is that according to the official website, the entry file is vue.runtime.esm.js,. ide/installation.html-sharp%E5%AF%B9%E4%B8%8D%E5%90%8C%E6%9E%84%E5%BB%BA%E7%89%88%E6%9C%AC%E7%9A%84%E8%A7%A3%E9%87%8A, E6%9C%89%E5%A4%A7%E4%BD%AC%E5%8F%AF%E4%BB%A5%E8%A7%A3%E9%87%8A%E4%B8%80%E4%B8%8B%E8%BF%99%E6%98%AF%E4%B8%BA%E4%BB%80%E4%B9%88%E5%90%97 "rel=" nofollow noreferrer "> https://cn.vuejs.org/v2/guide.