Pausing setInterval when page/ browser is out of focus

Immediately inside setInterval, place a check to see if the document is focused. The interval will continue firing as usual, but the code inside will only execute if the document is focused. If the window is blurred and later refocused, the interval will have continued keeping time but document.hasFocus() was false during that time, so there’s no need for the browser to “catch up” by executing the code block a bunch of times when focus is restored.

var timePerInterval = 7000;
$(document).ready(function() {
    setInterval(function(){
        if ( document.hasFocus() ) {
            // code to be run every 7 seconds, but only when tab is focused
        }
    }, timePerInterval );
});