JSFiddle - React, Tailwind, and code Playground

HTML

<button id="start">Start</button>
<button id="stop">Stop</button>

<p id="blink">Some text which blinking.</p>

JavaScript

var Blinker = {
    interval: null,
    start: function() {
        if (this.interval) return;
        this.interval = setInterval(function() {       
            $('#blink').toggle();
        }, 250);
    },
    stop: function() {
        clearInterval(this.interval);
        $('#blink').show();
        this.interval = null;
    }
}

//Initialize blink status.
var blinkStatus = 1;

//Check if status is changed, and run/stop blinking. 
setInterval(function() {
    if (blinkStatus == 1) {
        Blinker.start();
    }
    else {
        Blinker.stop();
    }
}, 250);

$('#start').on('click', function() {
    blinkStatus = 1;
});
$('#stop').on('click', function() {
    blinkStatus = 0;
});