timer

setInterval --- next timer

<script>
$(function(){
    var n=0;
    function run(){
        n=n+1;
        document.title =n;   // The browser tab bar displays the title 
    }
    setInterval(run,2000);
});
</script>

clearInterval --- clear the timer

var interval = setInterval(run(),1000);   // execute run() every second 
 
$( "").click( function (){   // click the pause button 
    if (interval){
        clearInterval(interval);
        interval = null;
    }
});
$( "").click( function (){   // Click the continue button 
    if (interval){
        clearInterval(interval);
        interval = null;
    }
    interval = setInterval(run(),1000);
});
 
function run(){
   
}