tabs标签页在切换的时候进行提示，点击确定执行，点击取消不切换

element文档：before-leave切换标签之前的钩子，若返回 false 或者返回 Promise 且被 reject，则阻止切换。

这里有个坑就是直接return false 不生效，用 Promise 的reject的才能阻止

<template><div style="width: calc(100% - 558px); text-align: left; flex: 1"><el-tabstype="card"v-model="current":before-leave="changeHeader"><el-tab-panev-for="item in list":label="item.title":key="item.name":name="item.path"></el-tab-pane></el-tabs></div>
</template><script>
export default {data() {return {};},mounted() {},methods: {// 导航栏切换菜单changeHeaderMenu(tab) {var p = new Promise((resolve, reject) => {this.$confirm("您页面有修改，是否继续跳转?", {confirmButtonText: "确实",cancelButtonText: "取消",type: "warning",}).then(async () => {resolve();this.changeFun(tab);}).catch(() => {// throw new Error('取消成功！')return reject();});});return p;},},
};
</script>