js使用浏览器的另存为下载文件

//判断浏览器类型
function myBrowser(){
var userAgent = navigator.userAgent; //取得浏览器的userAgent字符串
var isOpera = userAgent.indexOf("Opera") > -1;
if (isOpera) {
return "Opera"
}; //判断是否Opera浏览器
if (userAgent.indexOf("Firefox") > -1) {
return "FF";
} //判断是否Firefox浏览器
if (userAgent.indexOf("Chrome") > -1){
return "Chrome";
}
if (userAgent.indexOf("Safari") > -1) {
return "Safari";
} //判断是否Safari浏览器
if (userAgent.indexOf("compatible") > -1 && userAgent.indexOf("MSIE") > -1 && !isOpera) {
return "IE";
}; //判断是否IE浏览器
if (userAgent.indexOf("Trident") > -1) {
return "Edge";
} //判断是否Edge浏览器
}

function SaveAs5(imgURL)
{
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();
}

var odownLoad=null;
function downF(obj){
odownLoad = document.getElementById(obj);
var url = $(odownLoad).siblings("input[name='fgycompany.fileUrl']").val();
oDownLoad(url);
}

function oDownLoad(url) {
debugger;
myBrowser();
if (myBrowser()==="IE"||myBrowser()==="Edge"){
//IE
odownLoad.href="#";
var oImg=document.createElement("img");
oImg.src=url;
oImg.id="downImg";
var odown=document.getElementById("down");
odown.appendChild(oImg);
SaveAs5(document.getElementById('downImg').src)
}else{
//!IE
odownLoad.href=url;
odownLoad.download="";
}
}