问选项卡处于非活动状态时jQuery setInterval速度太快

EN

$(document).ready(function(){
    $([window, document]).focusin(function(){
       //code run when tab is selected
    }).focusin(function(){
       //code to stop all animation
    });
});

$(document).ready(function(){
  var i = 0;
  window.setInterval(function(){
    switch_pic(i++); // increase i after call
    if(i > 3) i = 0; // reset i
  }, 8000);
});

    var intervalId;

    $([window, document]).on('focusin', function(){
        intervalId = setInterval(function() {
            // Action in interval
        }, 3000);
    }).on('focusout', function(){
        if (intervalId) {
            clearInterval(intervalId);
        }
    });

intervalFunction();

$([window, document]).on('focusin', function(){
    if (!intervalId){
        intervalFunction();
    }
}).on('focusout', function(){
    if (intervalId) {
        clearInterval(intervalId);
        intervalId = undefined;
    }
});

function intervalFunction() {
    // Your function hire
}