为什么每次运行函数时if语句都与else交替出现

Question

So here i made a function from a button to upload images using ajax to show on the canvas but to specify the width and height I use the if statement. I specify if width greater than height the width = 300 and height = 200 , if width less than height width = 200 and height = 300 .

But i dont know how the if i click the button for first time after refresh my page the if statement is not correct or else sometime it is. And the next following click is alternately. Here my code.

      var image2 = new Image();   
      image2.src = '../img/template/'+e; 
      tmpWidht = parseInt(image2.width);
      tmpHeight = parseInt(image2.height);

      if( tmpWidht > tmpHeight ){
        var imgWidth = 300;
        var imgHeight = 200;
      }else{
        var imgWidth = 200;
        var imgHeight = 300;
      }

Answer 1

ah sorry this is the all of my success ajax code

var id = e+varImg;
      var image2 = new Image();   
      image2.src = '../img/template/'+e; 
      tmpWidht = parseInt(image2.width);
      tmpHeight = parseInt(image2.height);

      if( tmpWidht > tmpHeight ){
        var imgWidth = 300;
        var imgHeight = 200;
      }else{
        var imgWidth = 200;
        var imgHeight = 300;
      }

      image2.onload = function(){
        var img2 = new Konva.Image({
        x:50,
        y:50,
        width: imgWidth,
        height: imgHeight,
        image: image2,
        id: id,
        draggable: true
        });

      layer.add(img2);
      layer.draw();