Not working in strict mode

[MichaelZelensky]

If you use this in a script which is in strict mode, IE throws an error in Dev tools.

[riturajratan]

Have you fine any solution for that i am facing same issue

[shah-dhaval]

It's not working in strict mode because use of caller functionality which will throw error in strict mode. To make it work in strict mode you should remove use of caller. So other way of getting source of event is passing the event.target in setDragImage, so download source code and modify as below

DataTransfer.prototype.setDragImage = function(image, offsetX, offsetY, eventTarget) {
        var randomDraggingClassName,
            dragStylesCSS,
            dragStylesEl,
            headEl,
            parentFn;

        // generate a random class name that will be added to the element
        randomDraggingClassName = 'setdragimage-ie-dragging-' + Math.round(Math.random() * Math.pow(10, 5)) + '-' + Date.now();

        // prepare the rules for the random class
        dragStylesCSS = [
            '.' + randomDraggingClassName,
            '{',
            'background: url("' + image.src + '") no-repeat #fff 0 0 !important;',
            'width: ' + image.width + 'px !important;',
            'height: ' + image.height + 'px !important;',
            'text-indent: -9999px !important;',
            'border: 0 !important;',
            'outline: 0 !important;',
            '}',
            '.' + randomDraggingClassName + ' * {',
            'display: none !important;',
            '}'
        ];
        // create the element and add it to the head of the page
        dragStylesEl = document.createElement('style');
        dragStylesEl.innerText = dragStylesCSS.join('');
        headEl = document.getElementsByTagName('head')[0];
        headEl.appendChild(dragStylesEl);

        /*
        since we can't get the target element over which the drag start event occurred
        (because the `this` represents the DataTransfer object and not the element),
        we will walk through the parents of the current functions until we find one
        whose first argument is a drag event
         */
        //parentFn = DataTransfer.prototype.setDragImage.caller;
        //while (!(parentFn.arguments[0] instanceof DragEvent)) {
        / /   parentFn = parentFn.caller;
        //}

        // then, we get the target element from the event (event.target)
        //eventTarget = parentFn.arguments[0].target;
        // and add the class we prepared to it
        eventTarget.classList.add(randomDraggingClassName);

        /* immediately after adding the class, we remove it. in this way the browser will
        have time to make a snapshot and use it just so it looks like the drag element */
        setTimeout(function() {
            // remove the styles
            headEl.removeChild(dragStylesEl);
            // remove the class
            eventTarget.classList.remove(randomDraggingClassName);
        }, 0);
    };

To use it you will pass the event.target in fourth argument

function dragstart_handler(ev) {
 var img = new Image(); 
 img.src = 'example.gif'; 
 ev.dataTransfer.setDragImage(img, 10, 10, ev.target);
}