Getting image width on image load fails on IE

Question

I have a image resizer function that resize images proportional. On every image load a call this function with image and resize if its width or height is bigger than my max

Answer 1

Don't use width and height. Use naturalWidth and naturalHeight instead. These provide the image unscaled pixel dimensions from the image file and will work across browsers.

Answer 2

    var screenW = screen.width;
    var screenH = screen.height;
    //alert( screenW );
    function checkFotoWidth( img, maxw )
    {
        if( maxw==undefined)
            maxw = 200;
        var imgW = GetImageWidth(img.src);
        var imgH = GetImageHeight(img.src);
            //alert(GetImageWidth(img.src).toString()); // img.width); // objToString(img));
        if (imgW > maxw || (img.style.cursor == "hand" && imgW == maxw))
        {
            if (imgW > screenW) winW = screenW;
            else winW = imgW;

            if (imgH > screenH) winH = screenH;
            else winH = imgH;

            img.width=maxw;
            img.style.cursor = "pointer";

            img.WinW = winW;
            img.WinH = winH;
            //alert("winW : " + img.WinW);
            img.onclick = function() { openCenteredWindow("Dialogs/ZoomWin.aspx?img=" + this.src, this.WinW, this.WinH, '', 'resizable=1'); }
            img.alt = "Klik voor een uitvergroting :: click to enlarge :: klicken Sie um das Bild zu vergrössern";
            //alert("adding onclick);
        }
    }

    function GetImageWidth(imgSrc) 
    {
        var img = new Image();
        img.src = imgSrc;
        return img.width;
    } 

    function GetImageHeight(imgSrc) 
    {
        var img = new Image();
        img.src = imgSrc;
        return img.height;
    } 

Answer 3

This is how I solved it (because it's the only js on the site I didn't want to use a library).

    var imageElement = document.createElement('img');
    imageElement.src = el.href; // taken from a link cuz I want it to work even with no script
    imageElement.style.display      = 'none';

    var imageLoader = new Image();
    imageLoader.src = el.href;
    imageLoader.onload = function() {
        loaderElement.parentElement.removeChild(loaderElement);
        imageElement.style.position     = 'absolute';
        imageElement.style.top          = '50%';
        imageElement.style.left         = '50%';
        // here using the imageLoaders size instead of the imageElement..
        imageElement.style.marginTop    = '-' + (parseInt(imageLoader.height) / 2) + 'px';
        imageElement.style.marginLeft   = '-' + (parseInt(imageLoader.width) / 2) + 'px';
        imageElement.style.display      = 'block';
    }

Answer 4

Try

 function onImageLoad(img, maxWidth, maxHeight) {
   var width = img.width; // Problem is in here
   var height = img.height // Problem is in here
   if (height==0  && img.complete){
       setTimeOut(function(){onImageLoad(img, maxWidth, maxHeight);},50);
   }

 }

Answer 5

Man, I was looking for this for 2 days. Thanks.

I'm using jQuery, but it doesnt matter. Problem is related to javascript in IE.

My previous code:

var parentItem = $('<div/>')
   .hide();      // sets display to 'none'

var childImage = $('<img/>')
   .attr("src", src)
   .appendTo(parentItem)   // sets parent to image
   .load(function(){
      alert(this.width);  // at this point image is not displayed, because parents display parameter is set to 'none' - IE gives you value '0'
   });

This is working in FF, Opera and Safari but no IE. I was getting '0' in IE.

Workaround for me:

var parentItem = $('<div/>')
   .hide();

var childImage = $('<img/>')
   .attr("src", src)
   .load(function(){
      alert(this.width);  // at this point image css display is NOT 'none'  - IE gives you correct value
      childImage.appendTo(parentItem);   // sets parent to image
   });

Answer 6

It's because IE can't calculate width and height of display: none images. Use visibility: hidden instead.