var btn = document.getElementById("uploadImg");//上传的控件 var file = btn.files[0]; var reader = new FileReader(); reader.readAsDataURL(file); reader.onload = function(){ //读取完成后,数据保存在对象的result属性中 var img = new Image(); img.onload = function(){ console.log(img.wdith,img.height) } img.src = this.result; }