js 实时获得 img 标签尺寸，获得 img 原始尺寸

两种方式获得静态 img 尺寸

纯 js

var img = document.getElementById("demo-img");
console.log(img.width, img.height);

jQuery

$("#demo-img").load(function () {
    console.log(this.width, this.height);
});

添加 window.resize 获得动态 img 尺寸

$(window).resize(function () {
    var img = document.getElementById("demo-img");
    console.log(img.width, img.height);
});

img.naturalWidth 获得 img 原始尺寸

// 获取原始图片尺寸
var img = document.getElementById("demo-img");
var oriImgW = img.naturalWidth;
var oriImgH = img.naturalHeight;
console.log(oriImgW, oriImgH);