javascript 画像をキャッシュ化させないようにする

<img id="sample" />

<button id="btn">取得</button>

<script>

'use strict';

window.onload = function(){
    document.getElementById('sample').src = `sample.gif?${(new Date).getTime()}`
}

</script>

<img id="sample" src="sample.gif" />

<script>

'use strict';

window.onload = function(){
    document.getElementById('sample').src = document.getElementById('sample').src + `?${(new Date).getTime()}`
}

</script>

onload = () => { sample.src =  `${sample.src}?${(new Date).getTime()}` }