How to load image on demand

Question

I have this simple image zoom jQuery. Here is a Demo example. It uses the elevateZoom jQuery.

The code behind is very simple:

<img id="zoom_05" src='small_image1.png' data-zoom-image="large_image1.jpg"/>
<script>
   $vc("#zoom_05").elevateZoom({
  zoomType              : "inner",
  cursor: "crosshair"
});
</script>

My question, is how can i make the large image load on demand, only when the mouse is over it. Please have a look at this demo example and let me know what i need to add in the code.

Answer 1

img element (id="zoom_05") above, would not load large_image1.jpg on its own. Large image load happens because elevateZoom() looks into its data-zoom-image value and immediately loads it. One way around this behaviour is to defer elevateZoom() until user hover's over the small image for the first time. Quick example:

   jQuery( function () {

   var elevate_zoom_attached = false, $zoom_05 = $("#zoom_05") ;

    $zoom_05.hover(
     // hover IN
     function () {
        if ( ! elevate_zoom_attached ) {
        $zoom_05.elevateZoom({
                  zoomType : "inner",
                  cursor   : "crosshair"
                });
        elevate_zoom_attached = true ;
        };
    },
     // hover OUT
     function () {
        if ( elevate_zoom_attached) { // no need for hover any more
          $zoom_05.off("hover");
        }
     }
  );

}) ;

Mind you this is an quick, on-top-of-my-head code, but should work ... Also in this case elevateZoom() action might not be immediate while large image loading is going on.

Answer 2

I used this idea to initiate zoom on any number of images on the same page by adding a zoom class to the image. It works without any HOVER OUT

<img class="zoom" src="myimage.png" data-zoom-image="mybigimage.png"/>

$('.zoom').hover(
  // hover IN
  function () {

   var currImg = $(this); //get the current image
   if (!currImg.hasClass('zoomon')) { //if it hasn't been initialized
       currImg.elevateZoom(); //initialize elevateZoom
       currImg.addClass('zoomon'); //add the zoomon class to the img so it doesn't re-initialize
   }
})