<a href="url">点击链接下载</a>

var form = $("<form></form>").attr("action", url).attr("method", "post");

        form.append($("<input></input>").attr("type", "hidden").attr("name", "参数1").attr("value", "值1"));

        form.append($("<input></input>").attr("type", "hidden").attr("name", "参数2").attr("value", "值2"));

        form.appendTo('body').submit().remove();
//url为请求地址

var xhr = new XMLHttpRequest();

        var formData = new FormData();

        formData.append('参数1', "值1");

        formData.append('参数2',"值2");

        xhr.open('POST', url, true);

        xhr.setRequestHeader("token", token);     //可以带请求头

        xhr.responseType = 'blob';

        xhr.onload = function (e) {

            if (this.status == 200) {

                var blob = this.response;

                //var responseHeaders = xhr.getAllResponseHeaders();

                //var ContentDisposition = this.getResponseHeader("Content-Disposition");

                //var filename = this.getResponseHeader("Content-Disposition").split('filename=')[1];  
                // 获取文件名，需要在后端响应头暴露("Access-Control-Expose-Headers", "Content-Disposition");

                var filename = "xxxx.xxx";

                if (window.navigator.msSaveOrOpenBlob) {

                    navigator.msSaveBlob(blob, filename);

                } else {

                    blob.type = "application/octet-stream";

                    var url = URL.createObjectURL(blob);

                    var a = document.createElement('a');

                    a.href = url;

                    a.download = filename;

                    a.click();

                    window.URL.revokeObjectURL(url);

                }

            }else if(this.status == 404){

                alert("file does not exist!");

            }else{

                alert("failed to download file! ");

            }

        };

        xhr.send(formData);