之前有一篇写的如何同时传递form表单及upload组件文件，如果有多个upload文件该如何传递呢
上代码
html
<el-form ref="newform" :model="newform" :rules="rules">
<el-form-item prop="expName" label="">
<el-input v-model="newform.expName" placeholder="" style="width:75%">
</el-input>
</el-form-item>
<el-form-item prop="expSn" label="">
<el-input v-model="newform.expSn" placeholder="" style="width:75%">
</el-input>
</el-form-item>
<el-form-item label='' prop="groupName">
<el-select v-model="newform.groupName" placeholder="" style="width:75%" @change="newSelectGroup($event)">
<el-option
v-for="item in groupOptions"
:key="item.groupId"
:label="item.groupName"
:value="item.groupId">
</el-option>
</el-select>
</el-form-item>
<el-form-item label="" prop="subGroupName">
<el-select v-model="newform.subGroupName" placeholder="" style="width:75%" @change="newSelectSubGroup($event)">
<el-option
v-for="item in subGroupOptions"
:key="item.subGroupId"
:label="item.subGroupName"
:value="item.subGroupId">
</el-option>
</el-select>
</el-form-item>
<el-form-item label="" prop="expvmDifficulty">
<el-rate v-model="newform.expvmDifficulty" :max="5" style="line-height: 2;"></el-rate>
</el-form-item>
<el-form-item label="" prop="expvmInstruction">
<el-upload
class="upload-demo"
drag
ref="uploadhtml"
:action="upload_url"
:auto-upload="false"
:before-upload="newHtml"
accept=".html, .htm">
<div class="el-upload__text">将文件拖到此处，或<em>点击上传</em></div>
<div slot="tip" class="el-upload__tip">实验信息上传，只能传(.html/.htm)文件</div>
</el-upload>
</el-form-item>
<el-form-item label="" prop="expvmFiles">
<el-upload
class="upload-demo"
drag
ref="uploadfile"
:action="upload_url"
:auto-upload="false"
:before-upload="newFiles"
multiple>
<div class="el-upload__text">将文件拖到此处，或<em>点击上传</em></div>
<div slot="tip" class="el-upload__tip">实验信息附件上传，只能传(.file)文件</div>
</el-upload>
</el-form-item>
<el-form-item label="" prop="expvmVideo">
<el-upload
class="upload-demo"
drag
ref="uploadvideo"
