<el-button type="info" v-bind:pp="value2+'bbbbb'" ref="btn" @click="show($event)">change</el-button><br>.
console.log(this.$refs.btn.$attrs.pp);
<el-button type="info" v-bind:pp="value2+'bbbbb'" ref="btn" @click="show($event)">change</el-button><br>.
console.log(this.$refs.btn.$attrs.pp);