js method to call webcam

(function (window, document) {
   = {
    init: function (options) {
      /**
        * options attribute example
        * videoID: video control ID
        * canvasID: canvas control ID
        * fileID: The ID of the input control whose type is file
        * imageID: The ID of the img control
        * videoEnable: Whether to enable the camera
        * audioEnable: Whether to enable microphone
        * videoWidth: Video width
        * videoHeight: Video Height
        * photoWidth: photo width
        * photoHeight: photo height
        */

      _options = options;
      if (isMobileTerminal()) {
        initMobileTerminal();
      } else {
        initComputerTerminal();
      }
    },
    photo: function () {
      if (isMobileTerminal()) {
        photoMobileTerminal();
      } else {
        photoComputerTerminal();
      }
    }
  };

  let _options = null;

  function initComputerTerminal() {
    let videoDom = (_options.videoID);
    if (!videoDom) {
      alert('Video control is invalid');
      return;
    }

    let canvasDom = (_options.canvasID);
    if (!canvasDom) {
      alert('Canvas control is invalid');
      return;
    }
    ('width', _options.photoWidth + 'px');
    ('height', _options.photoHeight + 'px');

    let parameters = {
      video: _options.videoEnable ? {
        width: _options.videoWidth,
        height: _options.videoHeight
      } : false,
      audio: _options.audioEnable
    };

    (parameters)
      .then(function (MediaStream) {
         = MediaStream;
        ();
      }).catch(function (reason) {
        (reason);
        alert(reason);
      });
  }

  function photoComputerTerminal() {
    let videoDom = (_options.videoID);
    if (!videoDom) {
      alert('Video control is invalid');
      return;
    }


    let canvasDom = (_options.canvasID);
    if (!canvasDom) {
      alert('Canvas control is invalid');
      return;
    }

    let context = ('2d');
    (videoDom, 0, 0, _options.photoWidth, _options.photoHeight);
  }

  function initMobileTerminal() {
    let fileDom = (_options.fileID);
    if (!fileDom) {
      alert('File control is invalid');
      return;
    }

    ('accept', 'image/*');
    ('capture', 'camera');

    let canvasDom = (_options.canvasID);
    if (!canvasDom) {
      alert('Canvas control is invalid');
      return;
    }

    ('width', _options.photoWidth + 'px');
    ('height', _options.photoHeight + 'px');

    let imageDom = (_options.imageID);
    if (!imageDom) {
      alert('Image control is invalid');
      return;
    }

    ('change', function () {
      let file = [0];
      let reader = new FileReader();
       = function () {
        ('src', );

        setTimeout(function () {
          let context = ("2d");
          (imageDom, 0, 0, _options.photoWidth, _options.photoHeight);
        }, 300);
      };
      (file);
    });
  }

  function photoMobileTerminal() {
    let fileDom = (_options.fileID);
    ();
  }

  function isMobileTerminal() {
    if (/AppleWebKit.*Mobile/() || /Mobile/.test() || /MIDP|SymbianOS|NOKIA|SAMSUNG|LG|NEC|TCL|Alcatel|BIRD|DBTEL|Dopod|PHILIPS|HAIER|LENOVO|MOT-|Nokia|SonyEricsson|SIE-|Amoi|ZTE/.test())
      return /Android|webOS|iPhone|iPod|BlackBerry/();
    return false;
  }
})(window, document);