JavaScript检测图片是否已经加载完成
function isImageOk(img) { // During the onload event, IE correctly identifies any images // that weren't downloaded as not complete. Others should too. // Gecko-based browsers act like NS4 in that they report this // incorrectly: they always return true. if (!img.complete) { return false; } // However, they do have two very useful properties: naturalWidth // and naturalHeight. These give the true size of the image. If // it failed to load, either of these should be zero. if (typeof img.naturalWidth != "undefined" && img.naturalWidth == 0) { return false; } // No other way of checking: assume it's ok. return true; }