js下载文件到本地各种方法总结

一、此方法火狐有些版本是不支持的

window.location.href = 'https://*****.oss-cn-**.aliyuncs.com/*********';

二、为了解决火狐有些版本不支持,可以改成这种方式

window.location='https://*****.oss-cn-**.aliyuncs.com/*********';

三、该方法IE和火狐都可以,url表示要下载的文件路径

function(url){
    try {
          var elemIF = document.createElement("iframe");
          elemIF.src = url;
          elemIF.style.display = "none";
          document.body.appendChild(elemIF);
        } catch (e) {
          alert("下载异常！");
        }
}

四、form表单的形式

downloadFile(url){
      var form=$("<form>");
      form.attr("style","display:none");
      form.attr("target","");
      form.attr("method","get"); 
     form.attr("action",url);
      $("body").append(form);
      form.submit();//表单提交}
}

五、a标签的方式

function(url,name){
    var a = document.createElement("a");
     a.download = name + ".xls";
     a.href = url;
     $("body").append(a); // 修复firefox中无法触发click
     a.click();
     $(a).remove();
}

六、假如后台给的文件流

function (formData, url, name) {
  return new Promise((resolve, reject) => {
    var xhr = new XMLHttpRequest();
    xhr.open("POST", url, true); // 也可以使用POST方式，根据接口
    xhr.responseType = "blob"; // 返回类型blob
    // 定义请求完成的处理函数，请求前也可以增加加载框/禁用下载按钮逻辑
    xhr.onload = function () {
      // 请求完成
      if (this.status === 200) {
        // 返回200
        var blob = this.response;
        var reader = new FileReader();
        reader.readAsDataURL(blob); // 转换为base64，可以直接放入a表情href
        reader.onload = function (e) {
          // 转换完成，创建一个a标签用于下载
          var a = document.createElement("a");
          a.download = name + ".xls";
          a.href = e.target.result;
          $("body").append(a); // 修复firefox中无法触发click
          a.click();
          resolve(200)
          $(a).remove();
        };
      }
    };
    // 发送ajax请求
    xhr.send(formData);
  })
};

七、download.js（下面是download.js源码）

//download.js v4.2, by dandavis; 2008-2016. [CCBY2] see http://danml.com/download.html for tests/usage
// v1 landed a FF+Chrome compat way of downloading strings to local un-named files, upgraded to use a hidden frame and optional mime
// v2 added named files via a[download], msSaveBlob, IE (10+) support, and window.URL support for larger+faster saves than dataURLs
// v3 added dataURL and Blob Input, bind-toggle arity, and legacy dataURL fallback was improved with force-download mime and base64 support. 3.1 improved safari handling.
// v4 adds AMD/UMD, commonJS, and plain browser support
// v4.1 adds url download capability via solo URL argument (same domain/CORS only)
// v4.2 adds semantic variable names, long (over 2MB) dataURL support, and hidden by default temp anchors
// https://github.com/rndme/download
 
(function (root, factory) {
    if (typeof define === 'function' && define.amd) {
        // AMD. Register as an anonymous module.
        define([], factory);
    } else if (typeof exports === 'object') {
        // Node. Does not work with strict CommonJS, but
        // only CommonJS-like environments that support module.exports,
        // like Node.
        module.exports = factory();
    } else {
        // Browser globals (root is window)
        root.download = factory();
  }
}(this, function () {
 
    return function download(data, strFileName, strMimeType) {
 
        var self = window, // this script is only for browsers anyway...
            defaultMime = "application/octet-stream", // this default mime also triggers iframe downloads
            mimeType = strMimeType || defaultMime,
            payload = data,
            url = !strFileName && !strMimeType && payload,
            anchor = document.createElement("a"),
            toString = function(a){return String(a);},
            myBlob = (self.Blob || self.MozBlob || self.WebKitBlob || toString),
            fileName = strFileName || "download",
            blob,
            reader;
            myBlob= myBlob.call ? myBlob.bind(self) : Blob ;
      
        if(String(this)==="true"){ //reverse arguments, allowing download.bind(true, "text/xml", "export.xml") to act as a callback
            payload=[payload, mimeType];
            mimeType=payload[0];
            payload=payload[1];
        }
 
 
        if(url && url.length< 2048){ // if no filename and no mime, assume a url was passed as the only argument
            fileName = url.split("/").pop().split("?")[0];
            anchor.href = url; // assign href prop to temp anchor
              if(anchor.href.indexOf(url) !== -1){ // if the browser determines that it's a potentially valid url path:
                var ajax=new XMLHttpRequest();
                ajax.open( "GET", url, true);
                ajax.responseType = 'blob';
                ajax.onload= function(e){ 
                  download(e.target.response, fileName, defaultMime);
                };
                setTimeout(function(){ ajax.send();}, 0); // allows setting custom ajax headers using the return:
                return ajax;
            } // end if valid url?
        } // end if url?
 
 
        //go ahead and download dataURLs right away
        if(/^data:[w+-]+/[w+-]+[,;]/.test(payload)){
        
            if(payload.length > (1024*1024*1.999) && myBlob !== toString ){
                payload=dataUrlToBlob(payload);
                mimeType=payload.type || defaultMime;
            }else{            
                return navigator.msSaveBlob ?  // IE10 can't do a[download], only Blobs:
                    navigator.msSaveBlob(dataUrlToBlob(payload), fileName) :
                    saver(payload) ; // everyone else can save dataURLs un-processed
            }
            
        }//end if dataURL passed?
 
        blob = payload instanceof myBlob ?
            payload :
            new myBlob([payload], {type: mimeType}) ;
 
 
        function dataUrlToBlob(strUrl) {
            var parts= strUrl.split(/[:;,]/),
            type= parts[1],
            decoder= parts[2] == "base64" ? atob : decodeURIComponent,
            binData= decoder( parts.pop() ),
            mx= binData.length,
            i= 0,
            uiArr= new Uint8Array(mx);
 
            for(i;i<mx;++i) uiArr[i]= binData.charCodeAt(i);
 
            return new myBlob([uiArr], {type: type});
         }
 
        function saver(url, winMode){
 
            if ('download' in anchor) { //html5 A[download]
                anchor.href = url;
                anchor.setAttribute("download", fileName);
                anchor.className = "download-js-link";
                anchor.innerHTML = "downloading...";
                anchor.style.display = "none";
                document.body.appendChild(anchor);
                setTimeout(function() {
                    anchor.click();
                    document.body.removeChild(anchor);
                    if(winMode===true){setTimeout(function(){ self.URL.revokeObjectURL(anchor.href);}, 250 );}
                }, 66);
                return true;
            }
 
            // handle non-a[download] safari as best we can:
            if(/(Version)/(d+).(d+)(?:.(d+))?.*Safari//.test(navigator.userAgent)) {
                url=url.replace(/^data:([w/-+]+)/, defaultMime);
                if(!window.open(url)){ // popup blocked, offer direct download:
                    if(confirm("Displaying New Document

Use Save As... to download, then click back to return to this page.")){ location.href=url; }
                }
                return true;
            }
 
            //do iframe dataURL download (old ch+FF):
            var f = document.createElement("iframe");
            document.body.appendChild(f);
 
            if(!winMode){ // force a mime that will download:
                url="data:"+url.replace(/^data:([w/-+]+)/, defaultMime);
            }
            f.src=url;
            setTimeout(function(){ document.body.removeChild(f); }, 333);
 
        }//end saver
 
 
 
 
        if (navigator.msSaveBlob) { // IE10+ : (has Blob, but not a[download] or URL)
            return navigator.msSaveBlob(blob, fileName);
        }
 
        if(self.URL){ // simple fast and modern way using Blob and URL:
            saver(self.URL.createObjectURL(blob), true);
        }else{
            // handle non-Blob()+non-URL browsers:
            if(typeof blob === "string" || blob.constructor===toString ){
                try{
                    return saver( "data:" +  mimeType   + ";base64,"  +  self.btoa(blob)  );
                }catch(y){
                    return saver( "data:" +  mimeType   + "," + encodeURIComponent(blob)  );
                }
            }
 
            // Blob but not URL support:
            reader=new FileReader();
            reader.onload=function(e){
                saver(this.result);
            };
            reader.readAsDataURL(blob);
        }
        return true;
    }; /* end download() */
}));

用法：

download(fileUrl,name,"video/mp4");

具体更多的用法请参考官网，

注意 download.js第一个参数 是数据流，不是像oss那样的文件地址

原文来自于：https://blog.csdn.net/wodebokecsdn/article/details/88397665