function increase a number by click javascript
<body>
<div id="poke"><button>click here</button></div>
<div id="counter">0</div>
<script type='text/javascript'>
var poke = document.getElementById('poke');
var cmp = document.getElementById('counter');
poke.addEventListener('click', myfonction)
//===========================================================
function myfonction() {
cmp.innerHTML = parseInt(cmp.innerHTML) +1;
}
</script>
</body>