// 异步任务 封装
// 1,定义函数 
// 2，使用核心api(queueMicrotask,MutationObserver,setTimeout)
function runAsynctask (callback){if(typeof queueMicrotask ==="function" ){queueMicrotask(callback)}else if( typeof MutationObserver ==="function" ){const obs = new MutationObserver(callback)const divNode =document.createElement('div')obs.observe(divNode,{childList:true })divNode.innerHTML = 'sss'}else{setTimeout(callback,0)}
}