js下载图片到本地

$(function(){
//二维码
(function(){
var img_src = $('.qr_img')[0].src;
if(browserIsIe()){//假如是ie浏览器
$('.down_qr').on('click',function(){
img_src = $('.qr_img')[0].src;
DownLoadReportIMG(img_src);
});
}else{
$('.down_qr').attr('download',img_src);
$('.down_qr').attr('href',img_src);

$('.sutmit_btn').on('click',function(){
$('.down_qr').attr('download',img_src);
$('.down_qr').attr('href',img_src);
});
}

})();
});

function DownLoadReportIMG(imgPathURL) {
//如果隐藏IFRAME不存在，则添加
if (!document.getElementById("IframeReportImg"))
$('<iframe style="display:none;" id="IframeReportImg" name="IframeReportImg" onload="DoSaveAsIMG();" width="0" height="0" src="about:blank"></iframe>').appendTo("body");
if (document.all.IframeReportImg.src != imgPathURL) {
//加载图片
document.all.IframeReportImg.src = imgPathURL;
}
else {
//图片直接另存为
DoSaveAsIMG();
}
}
function DoSaveAsIMG() {
if (document.all.IframeReportImg.src != "about:blank")
window.frames["IframeReportImg"].document.execCommand("SaveAs");
}
//判断是否为ie浏览器
function browserIsIe() {
if (!!window.ActiveXObject || "ActiveXObject" in window)
return true;
else
return false;
}

<img class="qr_img" src= "" download="" />