js实现点击保存图片

<img src="29587e40dd86443dbad8a489cab3bcce.png" id="DemoImg" border="0" onclick="SaveAs5(this.src)">

function SaveAs5(imgURL) {

    var userAgent = navigator.userAgent; //取得浏览器的userAgent字符串
    var isOpera = userAgent.indexOf("Opera") > -1;
    if (userAgent.indexOf("compatible") > -1 && userAgent.indexOf("MSIE") > -1 && !isOpera) {
        var oPop = window.open(imgURL, "", "width=1, height=1, top=5000, left=5000");
        for (; oPop.document.readyState != "complete";) {
            if (oPop.document.readyState == "complete")
                break;
        }
        oPop.document.execCommand("SaveAs");
        oPop.close();
    } else {
        var a = document.createElement("a");
        a.href = imgURL;
        a.click();
    }
}