删除file控件的内容:
其中οnclick="channel.select();document.execCommand('delete')"中的channel为对应file控件的id;
<s:file id="channel" name="channel" value="文件上传"></s:file>
<input type="button" value="清空" onclick="channel.select();document.execCommand('delete')">
其中οnclick="channel.select();document.execCommand('delete')"中的channel为对应file控件的id;