浏览器工具函数

• 页面滚动到底部
• 判断是否安装某个软件

页面滚动到底部

/**
 * 页面滚动到底部
 * @param {number} distance 每次滚动的距离(单位是px)，默认为600
 * @param {number} interval 每次滚动的时间间隔(单位是ms)，默认为500
 */
function scrollToBottom(distance = 600, interval = 500) {
  let totalHeight = 0;
  let timer = setInterval(() => {
    window.scrollBy(0, distance);
    totalHeight += distance;
    
    if (totalHeight >= document.body.scrollHeight) {
      clearInterval(timer);
      resolve();
    }
  }, interval);
}

判断是否安装某个软件

原理：利用input聚焦失焦去判断

1. 如果浏览器检测到本地系统有对应的注册码，则会弹窗提示是否打开客户端软件，input失去焦点，判断安装了客户端
2. 否则 1s 后还没弹窗，判断没有安装客户端

/**
 * 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();
  let handler = this.registerEvent(target, "blur", onBlur);
  
  function onBlur() {
    successCb && successCb();
    handler.remove();
    clearTimeout(timeout);
    document.body.removeChild(target);
  }
  
  location.href = uri;
  
  let timeout = setTimeout(function () {
    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);
      },
    };
  }
}