已知视频组件的id名称为myVideo，以下哪句代码可以获取视频上下文？ A: this.videoCtx = wx.createCameraContext('myVideo') B: this.videoCtx = wx.createVideoContext('myVideo') C: this.videoCtx = wx.createAudioContext('myVideo') D: this.videoCtx = wx.getRecoderManager('myVideo')

如下代码，myVideo是<;video>;标签的ID，为控制视频快进3秒，代码正确的是（ ）。var video = document.getElementById("myVideo"); A: video.currentTime += 3; B: video.currentTime = 3; C: video.volume += 3; D: video.volume = 3;