定时器

    var poolTimer
    var maxNum = 10
    var poolFinish = false
    function startPool(id) {
        maxNum--
        if(poolTimer){
            clearTimeout(poolTimer);
        }
        if (poolFinish || maxNum < 1) {
            maxNum = 10
            poolFinish = false
           
            return
        }
        // you operation 
        poolTimer = setTimeout(function(){
            startPool(id)
        } , 3000);
       
    }