<body>
<input id="inp" width="11em" style='border-bottom-color: black'>
<script>
let inp=document.getElementById('inp');
inp.oninput=()=>{
let rText='';
let s=inp.value.replace(/\s+/g, '');
s.split('').forEach((it,i)=>{
if (i%3===0){
rText+=' ';
}
rText+=it;
});
inp.value=rText;
}
</script>
</body>
<body>
<button name="bt" value="1">1</button>
<button name="bt" value="2">2</button>
<button name="bt" value="3">3</button>
<script>
let sum=0;
let s=document.getElementsByName('bt');
s.forEach(item=>item.onmousedown=()=>btclick(item))
let btclick=(bt)=>{
sum=sum+parseInt(bt.value)
console.log(bt.value+' pressedDown'+' sum='+sum);
bt.style.background='green'
bt.onmousedown=()=>btUnClick(bt)
testAllBtIsPress(sum)
}
let btUnClick=(bt)=>{
bt.style.background='grey';
bt.onmousedown=()=>btclick(bt);
sum=sum-parseInt(bt.value)
console.log(bt.value+' pressedUP'+'sum='+sum);
}
let testAllBtIsPress=(a)=>{
if (a===6){alert('ТАДАМ!! AllButtonsPressed')}
}
</script>
</body>