javascript – 在img.onload上留下处理程序是内存泄漏？

这段代码在浏览器中导致内存泄漏是否正确？

/**
 * @param {Canvas2DRenderingContext} ctx
 * @param {string} url
 */
function loadImageDrawIntoCanvas(ctx,x,y,url) {
  var img = new Image();
  img.onload = function() {
    ctx.drawImage(img,y);
  }
  img.src = url;
};

我的理解是因为img是一个DOM元素,因为我用img.onload将JavaScript附加到它上面,浏览器永远不会垃圾收集它.要纠正我需要清除img.onload

/**
 * @param {Canvas2DRenderingContext} ctx
 * @param {string} url
 */
function loadImageDrawIntoCanvas(ctx,y);
    img.onload = null;          // detach the javascript from the Image
    img = null;                 // needed also so the closure doesn't keep
                                // a reference to the Image?
  }
  img.src = url;
};