动态增加下载

jQuery:

function download(src) {
var $a = $("").attr("href", src).attr("download", "img.png");
$a[0].click();
}
原生js:

function download(src) {
var $a = document.createElement('a');
$a.setAttribute("href", src);
$a.setAttribute("download", "");

var evObj = document.createEvent('MouseEvents');
evObj.initMouseEvent( 'click', true, true, window, 0, 0, 0, 0, 0, false, false, true, false, 0, null);
$a.dispatchEvent(evObj);

};