var eleTextarea = document.querySelector('textarea');

var eleButton = document.querySelector('input[type="button"]');

// 下载文件方法

var funDownload = function (content, filename) {

    var eleLink = document.createElement('a');

    eleLink.download = filename;

    eleLink.style.display = 'none';

    // 字符内容转变成blob地址

    var blob = new Blob([content]);

    eleLink.href = URL.createObjectURL(blob);

    // 触发点击

    document.body.appendChild(eleLink);

    eleLink.click();

    // 然后移除

    document.body.removeChild(eleLink);

};

if ('download' in document.createElement('a')) {

    // 作为test.html文件下载

    eleButton.addEventListener('click', function () {

        funDownload(eleTextarea.value, 'test.html');

    });

} else {

    eleButton.onclick = function () {

        alert('浏览器不支持');

    };

}

function downloadIamge(imgsrc, name) { //下载图片地址和图片名

    let image = new Image();

    // 解决跨域 Canvas 污染问题

    image.setAttribute("crossOrigin", "anonymous");

    image.onload = function () {

        let canvas = document.createElement("canvas");

        canvas.width = image.width;

        canvas.height = image.height;

        let context = canvas.getContext("2d");

        context.drawImage(image, 0, 0, image.width, image.height);

        let url = canvas.toDataURL("image/png"); //得到图片的base64编码数据

        let a = document.createElement("a"); // 生成一个a元素

        let event = new MouseEvent("click"); // 创建一个单击事件

        a.download = name || "photo"; // 设置图片名称

        a.href = url; // 将生成的URL设置为a.href属性

        a.dispatchEvent(event); // 触发a的单击事件

    };

    image.src = imgsrc;

}