How to obtain image size and image proportional scaling using javascript

The example in this article describes the method of obtaining the image size and scaling the image proportionally using javascript. Share it with everyone for your reference, the details are as follows:

Get the picture size:

var originImage = new Image();
function GetImageWidth(oImage) {
  if (originImage.src != oImage.src) originImage.src = oImage.src;
  return originImage.width;
}
function GetImageHeight(oImage) {
  if (originImage.src != oImage.src) originImage.src = oImage.src;
  return originImage.height;
}

Picture scaling:

function SetImage(ImgD, FitWidth, FitHeight) {
  var image = new Image();
  image.src = ImgD.src;
  if (image.width > 0 && image.height > 0) {
    if (image.width / image.height >= FitWidth / FitHeight) {
      if (image.width > FitWidth) {
        ImgD.width = FitWidth;
        ImgD.height = (image.height * FitWidth) / image.width;
      } else {
        ImgD.width = image.width;
        ImgD.height = image.height;
      }
    } else {
      if (image.height > FitHeight) {
        ImgD.height = FitHeight;
        ImgD.width = (image.width * FitHeight) / image.height;
      } else {
        ImgD.width = image.width;
        ImgD.height = image.height;
      }
    }
  }
}