小编Hlu*_*nok的帖子

var number = document.querySelector('.number');
var button = document.querySelector('button');

button.addEventListener('click', function() {
    counting(number, 2500);
})

function counting(elem, value) {
 var count = 0;
 var timerId = setInterval(function() {
  if (++count == value) clearInterval(timerId);
  elem.innerHTML = count;
 }, 3000/value);
}

<span class="number">0</span>
<button>Go</button>