兼容ie8的前端下載方法

背景:在xp系統上 ie8瀏覽器的下載需求,后端返回資源路徑.

方法:谷歌下采用aDown下載,ie采用window.open 觸發下載,如果不能自動自動下載,采用execCommand("SaveAs")進行文件保存做下載(ps:保存無法在下載列表中查看),當禁用window.open時采用iframe進行下載(ps:此方法注意跨域);

完整代碼如下,如發現bug及漏洞,請多交流.

var DownLoad = function (url, name) {
      if (!!window.ActiveXObject || "ActiveXObject" in window) {
        //ie
        var oPow = window.open(url, "", "width = 1, height = 1, top = 5000, left = 5000 ");
        var isOpen = true; //判斷window.open是否被禁用
        try {
          if (oPow == null) {
            isOpen = false
          }
        } catch (err) {
          isOpen = false
        }
        if (isOpen) {
          //沒禁用window.open采用window.open下載
          while (oPow.document.readyState !== "complete") {
            if (oPow.document.readyState === "complete") break;
          }
          oPow.document.execCommand("SaveAs", true, name);
          oPow.close();
        } else {
          //禁用了window.open采用iframe下載
          var oIrame = document.createElement('iframe');
          oIrame.style.width = "0px";
          oIrame.style.height = "0px";
          oIrame.style.opacity = 1;
          document.body.appendChild(oIrame)
          oIrame.src = url;
          var IfDoc = oIrame.contentDocument || oIrame.document;
          oIrame.onreadystatechange = function () { // IE下的節點都有onreadystatechange這個事件  
            if (oIrame.readyState == "complete") {
              // oIrame.execCommand("SaveAs", true, name)
              document.body.removeChild(oIrame)
            }
          };

        }

      } else {
        if (typeof url == 'object' && url instanceof Blob) {
          url = URL.createObjectURL(url); // 創建blob地址
        }
        var aLink = document.createElement('a');
        aLink.href = url;
        aLink.download = name || ''; // HTML5新增的屬性，指定保存文件名，可以不要后綴，注意，file:///模式下不會生效
        var event;
        if (window.MouseEvent) {
          event = new MouseEvent('click');
        } else {
          if (document.createEvent) {
            event = document.createEvent('MouseEvents');
            event.initMouseEvent('click', true, false, window, 0, 0, 0, 0, 0, false, false, false, false, 0, null);
          }
        }
        aLink.dispatchEvent(event);
      }

    }