添加placeholder

src/WebsiteManagement/marketproductMag/modules/add.vue

@@ -85,7 +85,7 @@
             </el-col>
             <el-col :span="24">
               <el-form-item :label="$t('分类')" prop="class">
-                <el-cascader ref="selectdep" size="small" style="width: 100%" v-model="form.classmx" :options="classData" filterable :props="{emitPath:false,expandTrigger:'hover',checkStrictly:false,label:'remarks',value:'value',children:'subvalues'}"  clearable></el-cascader>
+                <el-cascader ref="selectdep" size="small" style="width: 100%" :placeholder='$t("分类")' v-model="form.classmx" :options="classData" filterable :props="{emitPath:false,expandTrigger:'hover',checkStrictly:false,label:'remarks',value:'value',children:'subvalues'}"  clearable></el-cascader>
               </el-form-item>
             </el-col>
             <el-col :span="24">

src/WebsiteManagement/marketproductMag/modules/edit.vue

@@ -82,7 +82,7 @@
             </el-col>
             <el-col :span="24">
               <el-form-item :label="$t('分类')" prop="class">
-                <el-cascader ref="selectdep" size="small" style="width: 100%" v-model="form.classmx" :options="classData" filterable :props="{emitPath:false,expandTrigger:'hover',checkStrictly:false,label:'remarks',value:'value',children:'subvalues'}"  clearable></el-cascader>
+                <el-cascader ref="selectdep" size="small" style="width: 100%" :placeholder='$t("分类")' v-model="form.classmx" :options="classData" filterable :props="{emitPath:false,expandTrigger:'hover',checkStrictly:false,label:'remarks',value:'value',children:'subvalues'}"  clearable></el-cascader>
               </el-form-item>
             </el-col>
             <el-col :span="24">