JS检测客户端是否安装

   /**
     * uri 打开客户端的uri
     * failCb 打开客户端失败回调
     * successCb 打开客户端成功回调
     */
    function openUriWithInputTimeoutHack(uri, failCb, successCb) {
      let target = document.createElement('input')
      target.style.width = '0'
      target.style.height = '0'
          target.style.position = 'fixed'
      target.style.top = '0'
      target.style.left = '0'
      document.body.appendChild(target)
      target.focus();
      var handler = _registerEvent(target, "blur", onBlur);
      console.log('focus')
      function onBlur() {
        console.log('blur')
        successCb && successCb()
        handler.remove()
        clearTimeout(timeout)
        document.body.removeChild(target)
      };
      //will trigger onblur
      location.href = uri
      // Note: timeout could vary as per the browser version, have a higher value
      var timeout = setTimeout(function () {
        console.log('setTimeout')
        failCb && failCb()
        handler.remove()
        document.body.removeChild(target)
      }, 1000);
    }
    function _registerEvent(target, eventType, cb) {
        if (target.addEventListener) {
            target.addEventListener(eventType, cb);
            return {
                remove: function () {
                    target.removeEventListener(eventType, cb);
                }
            };
        } else {
            target.attachEvent(eventType, cb);
            return {
                remove: function () {
                    target.detachEvent(eventType, cb);
                }
            };
        }
    }
    // 测试
    let protocalUrl = `baseonline://`
    openUriWithInputTimeoutHack(protocalUrl, () => {
      console.log('检测到，未安装客户端')
    }, () => {
        // 浏览器弹窗提示
      console.log('检测到：已安装了客户端')
    })